A Hydrothermal Assisted Dehulling Process for Varieties of Sesame Seeds

Abstract

ABSTRACT A Hydrothermal Assisted Dehulling Process for Varieties of Sesame Seeds The present invention relates to a hydrothermal assisted dehulling process for varieties of sesame seeds. More particularly the present invention relates to efficient dehulling of sesame seeds by a hydrothermal process. The present invention includes the hydrothermal treatment on sesame seed for efficient dehulling without causing excessive breakage or loss of the kernel. The hydrothermal process enhances dehulling efficiency, reduce seed damage and cost, and improve overall quality of the dehulled seeds.

Specification

Description:FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)

1. TITLE OF THE INVENTION:
"A Hydrothermal Assisted Dehulling Process for Varieties of Sesame Seeds"
2. APPLICANT:
(a) Name : Junagadh Agricultural University
(b) Nationality : Indian
(c) Address : Agricultural Research Station, Junagadh Agricultural University, Amreli 365 601, Gujarat, INDIA.
PROVISIONAL
The following specification describes the invention. þCOMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.








FIELD OF INVENTION

The present invention relates to a dehulling process of sesame seeds. More particularly the present invention relates to a hydrothermal assisted dehulling process for varieties of sesame seeds. This invention aims to enhance dehulling efficiency, reduce hydration time period and seed damage and cost, and improve overall quality of the dehulled seeds.

BACKGROUND OF INVENTION
Sesame (Sesamum indicum L.) is an ancient oilseed crop used for its high oil content and rich nutritional value. The seeds are mainly utilized as a food ingredient in multiple forms, such as whole seeds, broken seeds, crushed seeds, shelled seeds, powdered seeds, and paste.
Beside to their rich nutritional content, sesame seeds have an outer layer known as the hull, which makes up 10-29% of their weight. This hull serves to protect the kernel from harsh environmental conditions, similar to many other seeds. Despite their high nutritional content, sesame seeds contain anti-nutrients in their hulls. The presence of anti-nutritional factors such as oxalic acid and phytates in the hull significantly reduces the bioavailability of zinc, calcium, magnesium, and iron. Oxalic acid, in particular, can diminish the biological utilization of calcium and affect taste. Additionally, the hull imparts a bitter taste, reducing the seed's palatability. These anti-nutritional components, such as oxalic acid and phytates, can be efficiently reduced from 3.5% to 0.25% in sesame by removing the hull through the dehulling process, greatly enhancing protein digestibility.
Usually, Oil is extracted from whole sesame seeds through mechanical pressing, but the seed hulls can cause rapid wear and tear on the machinery. Dehulling the seeds before oil extraction can enhance the oil's quality by reducing wax and improving color. Additionally, dehulling reduces physical damage to the oil extraction machinery by eliminating the abrasive hulls. The hull diminishes the nutritional value of the de-oiled meal and lowers the oil recovery rate. Dehulling sesame seeds may also beneficial for recovering the hulls, which can be used as a lignan concentrate, a health-enhancing compound. Hulled sesame seeds are softer and more flavourful than unhulled seeds. Dehulled sesame seeds and their products have strong potential in both domestic and export markets. Therefore, dehulling is crucial for enhancing the production of best quality oil as well as seed cake.
The efficiency and economy of the sesame seed dehulling process rely on effectively removing the hull without causing excessive breakage or loss of the kernel. Due to their small size and tightly bound pericarp, sesame seeds are challenging to dehull. Hydration of sesame seeds is an essential step to loosen the bond between the hull and cotyledon, facilitating the dehulling process.
One such process for dehusking of sesame seeds is disclosed in patent IN202341039361 that determines a method for producing textured vegetable protein. Initially, sesame seeds are meticulously cleaned and washed using mechanical vibrator machines to eliminate impurities. Subsequently, the seeds are dehulled, and the resulting kernels are subjected to a screw oil press machine to extract the oil. The problem associated in this process is the longer cooling time of sesame seeds and loss of nutrients.

CN202110166159A patent relates to a high-sesam in sesame oil production and preparation process. The preparation includes selection, soaking, stir frying, sieving, dehulling and then oil production. But this process requires longer soaking time and it also does not disclose the standardize method of dehulling.
Therefore, to standardize the dehulling process, it is essential to have a thorough understanding of the hydration characteristic of sesame seeds. The hydrating sesame seeds are inconvenient, laborious, and time consuming, often requiring up to 4 hours at ambient temperature. This prolonged hydration period can compromise the quality of dehulled sesame seeds during long-term storage. Thus, maintaining the quality and storability of dehulled sesame seeds poses a significant challenge for producers, distributors, and consumers. To reduce the risk of seed quality deterioration and solid leaching throughout soaking, it is essential to shorten the water soaking time. The hydration of seeds largely depends on both water soaking time and its temperature. The High hydration temperatures during soaking increase moisture diffusivity, leading to a rise in hydration rate and consequently dropping the water soaking period.
Hence, to overcome the above mentioned problem it is desperately needed to invent a suitable process for sesame seed dehulling. The basic aim of this research was to optimize and characterize sesame soaking time, hydration temperature, and retention time to maximize dehulling efficiency and minimize loss during the dehulling process.

OBJECT OF THE INVENTION

The principal object the present invention is to provide a hydrothermally assisted dehulling process for varies of sesame seeds.

Another object of the present invention is to generate the information and to standardize the hydrothermal assisted sesame dehulling process for getting better dehulling attributes. The developed dehulling method is cost effective and commercially viable option for the sesame dehulling industries.

Another object of the present invention is to study the water absorption kinetics of different sesame cultivars.

Yet another object of the present invention is to investigate the dehulling attributes of different sesame cultivars in relation to variable parameters.

Still another object of the present invention is to standardize the variety specific dehulling process parameters for different sesame cultivars.

Still another object of the present invention is to examine the relation between seed dehulling characteristics and selected physicochemical parameters of sesame seed.

SUMMARY OF INVENTION

The present invention discloses a hydrothermal assisted dehulling process for verities of sesame seeds. The process involves an initial cleaning step to remove impurities and defective seeds. Subsequently, the cleaned sesame seeds are soaked in hot water, followed by a drying process. The seeds are then dehulled using an indigenous low cost on farm sesame dehuller. After dehulling, the seeds are subjected to fractionation and stored for further use.

DETAILED DESCRIPTION OF INVENTION

Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details. The invention is capable of other embodiment and of being practiced or carried out in a variety of ways. It is to be understood that the phraseology and terminology employed herein is for the purpose of description and not of limitation.

The sesame dehulling process is vital for optimizing the quality and usability of sesame seeds in various culinary and industrial applications. By removing the outer hull, this process enhances the nutritional value of the seeds, making essential vitamins and minerals more bioavailable. It also significantly improves flavor and texture, ensuring that products meet consumer expectations for taste and quality.

Moreover, efficient dehulling increases the yield of usable kernels, reducing waste and lowering production costs, which is critical in meeting the growing market demand for hulled sesame seeds across diverse food sectors. This process also contributes to food safety by minimizing potential contaminants associated with hulls, aligning with stringent regulatory standards. Ultimately, the sesame dehulling process is essential for enhancing product quality, addressing consumer preferences, and supporting sustainable food production practices.

The sesame dehulling process is a critical operation in the preparation of sesame seeds for various culinary and industrial applications.

This process typically involves several key stages: initial seed cleaning, dehulling, and final separation of hulls from kernels.
Cleaning the Sesame Seeds:
Start by cleaning the sesame seeds to remove any foreign materials, damaged, cracked, or scratched seeds.
Hydrothermal treatment to sesame Seeds:
Heat water to 50°C to 55 °C and prepare a conditioning bath for the sesame seeds. Immerse the sesame seeds in the hot water for 72 to 75 minutes. This step softens the hulls of the seeds, making it easier to remove them during dehulling.
Removing Surface Moisture:
After the conditioning process, remove the sesame seeds from the water and drain them thoroughly. Spread the seeds out on a clean surface to remove surface moisture. The goal is to make sure the seeds are slightly damp but not too wet, as excess moisture can affect the dehulling process. Leave the seeds in ambient air or use a fan for quick drying until the surface moisture is removed.
Dehulling the Sesame Seeds:
Use a developed indigenous sesame dehuller to dehull the conditioned sesame seeds. This device should be suitable for handling small to medium-scale operations. Set the machine to dehulled the sesame seeds for 6 to 8 minutes. During this time, the machine will remove the hulls from the seeds, separating them from the kernels inside.
Fractioning the Dehulled Seed Mixture:
After the dehulling process, the mixture will contain different fractions, including: Dehulled seeds: (Seeds with their hulls removed), Unhulled seeds (Seeds where the hull was not fully removed), Broken seeds/meal (Small pieces of broken seeds and sesame meal) and Hull (The husks that were separated from the seeds), Use appropriate sieving or screening methods to separate these fractions based on their size.
Collect the Dehulled Sesame Seeds:
Once the sesame seeds have been dehulled and separated from the other fractions, collect the dehulled seeds. Make sure that the dehulled seeds are free from hulls, broken seeds, and other residues before moving on to storage.
Storage:
Store the dehulled sesame seeds in a plastic bag at room temperature. Ensure that the bag is sealed properly to protect the seeds from moisture, contamination, and insects. Sesame seeds should be stored in a cool, dry place, away from direct sunlight or heat sources. When stored under proper conditions, the seeds can maintain their quality for several months.

Experimental procedure
Materials
The sesame seed (variety: Gujarat Til 3 and Gujarat Til 4 were collected and used for all decided variables and its replications. The required sesame seed were cleaned, sorted for removing undesirable materials like dust, dirt, stones and immature seeds and finally dried. The dried seeds were packed in air tight plastic bag and stored. Desired amount of material was extracted from the bag as and when required for experiments.
Table 1:
Characteristics Gujarat Til 3 Gujarat Til 4
Morphological characters of plant
Pedigree adaptability G.Til 1 x AHT-85 G.Til 1 X RT 125
Stem hairiness Glabrous Glabrous
Capsule hairiness Glabrous Glabrous
Capsule arrangement Single opposite Multi alternate
Capsule length Long Medium
Seed size Bold Medium
Seed Color White White
Capsule hairiness Glabrous Glabrous
Biochemical Parameters seed
Moisture content (%, w.b) 4.36 4.18
Oil content (%) 47.32 48.6
Protein content 23.48 24.62
Carbohydrate content 12.88 11.21
Fibre content 4.36 3.98
Ash content 4.12 4.04
Physical Parameters seed
Length (mm) 3.11 3.19
Width (mm) 1.75 1.80
Thickness (mm) 0.87 0.88
Arithmetic mean diameter (mm) 1.91 1.96
Geometric mean diameter (mm) 1.68 1.72
Sphericity 0.54 0.54
Volume (mm3) 2.62 2.8
Volumetric expansion coefficient 1.01 1.05
Flakiness ratio 0.5 0.49
Elongation ratio 1.79 1.78
Aspect ratio 56.3 56.58
Surface area (mm2) 5.29 5.4
Projected area (mm2) 4.3 4.53
Thousand seeds weight (g) 2.86 3.03
Bulk density (kg/m3) 723.12 726.31
True density (kg/m3) 1034.08 1045.26
Porosity 30.06 30.48
Compressibility index 5.94 4.59
Hausner ratio 1.06 1.05
Tapped densities (kg/m3) 769.18 761.36
Angle of repose 32.16 32.4
Coefficient of friction 0.46 0.46
Terminal velocity (m/s) 5.82 5.88
Drag coefficient of the sesame seed 0.32 0.31
Reynolds number 670.68 685.16
Hardness (N/mm2) 9.66 9.73

Hydration of sesame seeds (Gujarat Til 3 and Gujarat Til 4)

Water soaking experiments were carried out for sesame seed at 35, 45 and 55±1 °C water temperatures. About 4 kg of sesame seeds packed in perforated cloth bag were conditioned distinctly in distill water available with pre-decided desired temperatures in thermostatically controlled water bath. Before each experiment, the distilled water in the container was kept in the desired temperature for a few minutes to reach to equilibrium. At selected intervals of time, 500 gm of sesame seeds were swiftly extracted and crucially eliminating the surface moisture using filter paper. These analyzed seeds were cast off afterward. The solids losses as a result of oozing during hydration were assessed by determining the specific gravity of pure water and water drained after the soaking process was found to be less than 1% and was, therefore, considered negligible.

Dehulling of sesame seed (Gujarat Til 3 and Gujarat Til 4)
The sesame seed samples were dehulled by using a sesame dehuller. The dehulling process for various sesame seed samples was conducted according to the treatment combinations. After dehulling samples were removed from the dehuller and dried in a tray dryer at 50 °C for overnight to achieve lower moisture contents (< 2%, w.b) for easy separation process. The dehulled seed mixture was sieved using 18 mesh size sieve to separate seed broken and meal from the dehulled sesame seed mixture. The broken seed and meal was weighed and fraction retained on 18 mesh size sieve was fed in to 30 mesh size sieve for separation of hull. The dehulled and unhulled sesame seed were manually separated for further analysis. The optimization of the dehulling process was based on the results of response parameters. A central composite rotatable design (CCRD) includes a set of empirical methods for discovering the comparative impact of the independent variables viz. water soaking time (X1=60-120 min.), hydration temperature (X2 =35-55 ºC) and retention time (X3= 5-7 min.) on the measured responses (Dehulling efficiency, Hullability, Yield loss, Embryo recovery and Extraction rate) according to one or more selected criteria.

RESULTS AND DISCUSSION OF VARIETIES (GUJARAT TIL 3)
The effect of variables and their levels on dehulling parameters are described below.
The wide variations in all the responses were observed for different experimental combinations and are presented in Table 2.
Table 2: Responses results of different runs as per RSM
Runs Process Variables Responses
WST
(min.) HT
(°C) RT
(min.) DE
(%) H
(%) YL
(%) ER
(%) Er
(%)
1 60 35 5 72.83 70.72 9.03 71.57 90.97
2 120 35 5 82.10 77.99 9.82 81.08 90.18
3 60 55 5 77.75 76.15 9.51 76.55 90.49
4 120 55 5 84.80 76.43 9.83 84.10 90.17
5 60 35 7 75.42 71.55 9.04 74.47 90.96
6 120 35 7 84.16 79.37 9.97 83.22 90.03
7 60 55 7 79.61 77.90 9.84 78.27 90.16
8 120 55 7 89.60 83.43 10.53 88.71 89.47
9 60 45 6 79.18 77.72 9.86 77.76 90.14
10 120 45 6 87.35 83.89 10.67 86.03 89.33
11 90 35 6 80.75 74.95 9.61 79.81 90.39
12 90 55 6 86.63 80.85 10.27 85.66 89.73
13 90 45 5 84.38 77.99 10.00 83.44 90.00
14 90 45 7 87.26 80.94 10.35 86.29 89.65
15 90 45 6 86.36 81.58 10.21 85.42 89.79
16 90 45 6 87.48 79.65 10.21 86.69 89.79
17 90 45 6 87.01 78.82 9.98 86.41 90.02
18 90 45 6 85.02 76.80 9.69 84.50 90.31
19 90 45 6 86.55 79.74 10.19 85.66 89.81
20 90 45 6 87.73 80.76 10.15 87.04 89.85
WST = Water soaking time, HT = hydration temperature, RT = Retention time, DE = Dehulling efficiency, H = Hullability, YL = Yield loss, ER = Embryo recovery, E= Extraction rate
Dehulling efficiency (DE)
In order to understand the contribution of different variables viz. water soaking time (WST), hydration temperature (HT) and retention time (RT) in regards to responses (Dehulling efficiency, Hullability, Yield loss, Embryo recovery and Extraction rate), a multiple regression analysis of data obtained was performed using Design Expert software. The data for all he dependent variables were simultaneously fitted to quadratic models in the software (Table 2). Regression analysis was applied to fit a full response surface model for every response calculated including all linear, interaction and quadratic terms. The regression coefficients for the response surface model in terms of coded units are shown in Table 2.
The effect of independent variables on dehulling efficiency is noted in Table 3. The dehulling efficiency ranged from 72.83 to 89.60 % during different dehulling runs (Table 2). The water soaking time, hydration temperature and retention time had significant positive linear and negative quadratic effects except retention time on dehulling efficiency. While all other interaction effect as well as quadratic effect of retention time were found non-significant (p>0.05). The tabular results clearly confirmed the rising trend of dehulling efficiency with increase in water soaking time, hydration temperature and retention time. With respect to the combination, at 120 min. water soaking time, 55 °C hydration temperature and 7 min. retention time had highest dehulling efficiency values (89.60 %) whereas at 60 min. water soaking time, 35 °C hydration temperature and 5 min. retention time had lowest dehulling efficiency depicting positive relationship of rising water soaking time and hydration temperature and its effect on dehulling efficiency.
Table 3: ANOVA and regression coefficients responses as influenced by independent parameters.

Coefficients Response
DE H YL ER Er
Model Quadratic (S) Quadratic (S) Quadratic (S) Quadratic (S) Quadratic (S)
Intercept 85.49*** 70.72*** 9.15*** 85.64*** 90.85***
Linear
X1 4.45*** 3.85*** 0.48*** 4.45*** -0.48***
X2 2.31*** 1.96*** 0.24*** 2.31*** -0.24***
X3 1.39*** 1.11** 0.12* 1.42*** -0.12*
Interactions
X1X2 0.005 -0.002 0.036 -0.035* -0.036
X1X3 0.256 0.307 0.019 0.265 -0.019
X2X3 0.230 0.622 0.087 0.160 -0.087
Quadratic
X12 -3.29*** -3.06*** -0.38*** -3.27*** 0.38***
X22 -2.49*** -2.48** -0.32** -2.43*** 0.32**
X32 -0.13 1.24 0.15 -0.31 -0.15
R2 0.98 0.97 0.96 0.98 0.96
Adj-R2 0.96 0.93 0.93 0.96 0.93
Pred-R2 0.87 0.81 0.92 0.85 0.92
Adeq. Pre. 24.52 19.09 17.95 24.03 17.95
SD 0.94 1.03 0.13 0.96 0.13
Mean 82.54 68.57 8.88 82.63 91.12
C.V. % 1.14 1.50 1.50 1.17 0.15
F-value 51.69 30.86 28.75 49.60 28.75
Lack of fit NS NS NS NS NS
X1= WST, X2 = HT and X3 = RT, ***Significant at p<0.001, **Significant at p<0.01, *Significant at p<0.05, NS = Non-significant
Hullability (H)
The variation of hullability was studied against the selected independent variables like water soaking time, hydration temperature as well as retention time and presented Table 2. The quadratic model was fitted to the experimental data and statistical significance of linear, quadratic and interaction effects were calculated for each response and are given in Table 3. The mean value of the hullability ranged from 70.72 to 83.89 % for different treatments combination (Table 3). The all the independent variables gave positive significant (p<0.001) linear outcome for hullability. The quadratic effects of water soaking time and hydration temperature on hullability were also found significant whereas retention time reported non-significant results. From the data, it can be observed that increase in water soaking time, hydration temperature as well as retention time, increased hullability which is a desired property.

Yield loss (YL)
Yield loss for sesame seed during dehulling was ranged from 9.03 to 10.67 % (Table 3). The effect of water soaking time, hydration temperature and dehulling time on yield loss is presented in Table 3. The tabular results shows the significantly rose in yield loss with increase in water soaking time, hydration temperature as well as retention time. The individual positive effect of water soaking time (p<0.001), hydration temperature (p<0.001) and retention time (p<0.05) while quadratic effects of water soaking time (p<0.001) and hydration temperature (p<0.01) were found to be significant. While all other interaction effect as well as quadratic effect of retention time were reported as non-significant (p>0.05).
Embryo recovery (ER)
The effect of water soaking time, hydration temperature and dehulling time on embryo recovery of is reported in Table 3. The regression coefficients indicated that at the linear level, all the independent parameters given significant positive effect on embryo recovery (Table 3). The embryo recovery of sesame seed ranged from 71.57 - 88.71 % (Table 3). The quadratic (p<0.001) and interaction (p<0.05) effect of water soaking time and hydration temperature shows positive significant where as others shows non-significant effect on embryo recovery.
Extraction rate (Er) (%)
The assessment of extraction rate as affected by dehulling parameters is indicated in Table 2. The regression analyses of data pertaining to extraction rate in dehulling process are presented in Table 2. The water soaking time (p<0.001), hydration temperature (p<0.001) and retention time (p<0.05) shown the significant negative individual effect while positive quadratic effect of water soaking time (p<0.001) and hydration temperature (p<0.01) found to be significant. The extraction rate values of dehulled sesame seed samples ranged from 89.33 to 90.97 % (Table2). The data about extraction rate of the sesame seed were found to be varied with the varying independent parameters. The highest extraction rate (93.29 %) was obtained with the lowest water soaking time and hydration temperature (Table 2).
Table 4 shows the suggested model equations for the particular responses. The reasonable agreements were found between adjusted-R2 and predicted-R2 for all the responses. All the parameters showed high adequate precision (>4) and low value of coefficient of variation of the model explained that the experimental results were precise and reliable.

Table 4 Predictive regression models for responses

Parameters Fitted models R2
DE (%) 85.49 + 4.45X1 + 2.31X2 + 1.39X3 + 0.005X1X2 + 0.256X1X3 + 0.230X2X3 - 3.29X1² - 2.49X2² - 0.13X3² 0.98
H (%) 70.72 + 3.85X1 + 1.96X2 + 1.11X3 - 0.002X1X2 + 0.307X1X3 + 0.622X2X3 -3.06X1² - 2.48X2² + 1.24X3² 0.97
YL (%) 9.15 + 0.48X1 + 0.24X2 + 0.12X3 + 0.036X1X2 + 0.019X1X3 + 0.087X2X3 - 0.38X1² - 0.32X2² + 0.15X3² 0.96
ER (%) 85.64 + 4.45X1 + 2.31X2 + 1.42X3 - 0.035X1X2 + 0.265X1X3 + 0.160X2X3 - 3.27X1² - 2.43X2² - 0.31X3² 0.98
Er (%) 90.85 - 0.48X1 - 0.24X2 - 0.12X3 - 0.036X1X2 - 0.019X1X3 - 0.087X2X3 + 0.38X1² + 0.32X2² - 0.15X3² 0.96

Table 4 shows the criteria for optimization, solution along with predicted and actual response values. The importance of level 3 was given to the constraints of water soaking time, hydration temperature and retention time. The process variables for the best combination of the responses (Desirability: 0.75) were water 74.50 min. water soaking time, 50°C hydration temperature and 7 min. retention time. The response functions were calculated from the final polynomial. The responses at this optimized combination were dehulling efficiency (84.06 %), hullability (70.76 %), yield loss (9.13 %), embryo recovery (84.06 %) and extraction rate (90.87 %). The experimentally arrived values and values predicted by the equations of the model were tested using t-test and there was no significant difference recorded between the actual and predicted values (P<0.05). Closeness between the experimental and predicted values of responses further verified by calculating percentage coefficient of variation and values were less than 5 % indicated the suitability of the corresponding models to predict responses.


Optimisation and Validation

Numerical optimization of independent variable levels was carried out using Design Expert for simultaneous optimization of the responses. The water soaking time of independent variables were kept minimum whereas other in range. Desired goals were assigned for all the parameters for obtaining the numerical optimum values for the responses. Response parameter like dehulling efficiency were kept maximum while, others responses were set in range.

Table 5 Constraints, criteria for optimization, solution along with predicted and actual response values.
Constraints Target Optimized (Predicted) value Experimental value Desirability
Water soaking time (min.) In range 74.40 74.50 0.75
Hydration temperature (°C) In range 50.08 50
Retention time (min.) In range 7.00 7
Responses
Dehulling efficiency (%) Maximum 84.06 83.92 ± 0.55
Hullability (%) None 70.76 70.11 ± 0.39
Yield loss (%) None 9.13 9.27 ± 0.16
Embryo recovery (%) None 84.06 83.97 ± 0.63
Extraction rate (%) None 90.87 91.06 ± 0.42

Table 5 demonstrates that experimental values for water soaking time, hydration temperature and retention time closely align with the optimized values, indicating the process step has been optimized. Additionally, the response values are very similar to the predicted ones, further confirming the optimization of the process and at the specified parameters; the results are even more improved.

RESULTS AND DISCUSSION OF VARIETIES (GUJARAT TIL 4)
The effect of variables and their levels on dehulling parameters are described below.
The wide variations in all the responses were observed for different experimental combinations and are presented in Table 6.
Table 6 Responses results of different runs as per RSM
Runs Process Variables Responses
WST
(min.) HT
(°C) RT
(min.) DE
(%) H
(%) YL
(%) ER
(%) Er
(%)
1 60 35 5 69.90 59.69 7.77 69.84 92.23
2 120 35 5 82.60 69.84 9.18 82.53 90.82
3 60 55 5 77.45 65.67 8.72 77.26 91.28
4 120 55 5 86.41 71.65 9.38 86.59 90.62
5 60 35 7 72.92 60.78 7.94 73.04 92.06
6 120 35 7 87.37 72.10 9.62 87.40 90.38
7 60 55 7 76.54 63.77 8.37 76.63 91.63
8 120 55 7 89.88 75.00 10.04 89.75 89.96
9 60 45 6 79.75 67.93 8.88 79.67 91.12
10 120 45 6 88.87 75.27 9.73 88.96 90.27
11 90 35 6 81.65 68.39 8.84 81.85 91.16
12 90 55 6 87.71 73.01 9.75 87.63 90.25
13 90 45 5 84.92 71.47 9.30 85.00 90.70
14 90 45 7 86.51 72.64 9.43 86.65 90.57
15 90 45 6 84.86 71.74 9.40 84.82 90.60
16 90 45 6 86.06 71.47 9.46 86.11 90.54
17 90 45 6 87.08 73.73 9.75 86.93 90.25
18 90 45 6 88.41 73.37 9.58 88.61 90.42
19 90 45 6 85.38 71.47 9.31 85.51 90.69
20 90 45 6 86.49 73.19 9.72 86.30 90.28
WST = Water soaking time, HT = hydration temperature, RT = Retention time, DE = Dehulling efficiency, H = Hullability, YL = Yield loss, ER = Embryo recovery, E= Extraction rate


Dehulling efficiency (DE)
In order to understand the contribution of different variables viz. water soaking time (WST), hydration temperature (HT) and retention time (RT) in regards to responses (Dehulling efficiency, Hullability, Yield loss, Embryo recovery and Extraction rate), a multiple regression analysis of data obtained was performed using Design Expert software. The data for all he dependent variables were simultaneously fitted to quadratic models in the software (Table 2). Regression analysis was applied to fit a full response surface model for every response calculated including all linear, interaction and quadratic terms. The regression coefficients for the response surface model in terms of coded units are shown in Table 6.
The effect of independent variables on dehulling efficiency is noted in Table 6. Across various dehulling runs, dehulling efficiency ranged from 69.90% to 89.88% (Table 6). The water soaking time and hydration temperature reported significant positive linear (p<0.001)and negative quadratic(p<0.01) effect on dehulling efficiency. The individual effect of retention time (p<0.01) also exhibited positive influence on dehulling efficiency. In addition to that, all interaction effects and the quadratic effect of retention time were found to be non-significant (p>0.05). The tabular data visually confirms the increasing trend of dehulling efficiency with higher water soaking time, hydration temperature, and retention time. Notably, the combination of 120 min. of water soaking time, a hydration temperature of 55°C, and a retention time of 7 min. resulted in the highest dehulling efficiency values (89.88%). Conversely, the lowest dehulling efficiency was observed at 60 minutes of water soaking time, a hydration temperature of 35°C, and a retention time of 5 minutes, indicating a positive relationship between increased water soaking time and hydration temperature and their impact on dehulling efficiency.


Table 7 ANOVA and regression coefficients table of responses as influenced by independent parameters

Coefficients Response
DE H YL ER Er
Model Quadratic (S) Quadratic (S) Quadratic (S) Quadratic (S) Quadratic (S)
Intercept 86.61*** 72.79*** 9.54*** 86.63*** 90.46***
Linear
X1 5.86*** 4.60*** 0.63*** 5.88*** -0.63***
X2 2.36*** 1.83*** 0.29*** 2.32*** -0.29***
X3 1.19** 0.60 0.11 1.22** -0.11
Interactions
X1X2 -0.606 -0.532 -0.095 -0.575 0.095
X1X3 0.766 0.804 0.160 0.682 -0.160
X2X3 -0.654 -0.238 -0.038 -0.693 0.038
Quadratic
X12 -2.64** -1.64* -0.24 -2.70** 0.24
X22 -2.27** -2.54** -0.25 -2.27** 0.25
X32 -1.23 -1.19 -0.18 -1.19 0.18
R2 0.97 0.97 0.94 0.97 0.94
Adj-R2 0.95 0.94 0.89 0.95 0.89
Pred-R2 0.86 0.78 0.56 0.88 0.56
Adeq. Pre. 21.73 19.68 14.74 22.02 14.74
SD 1.25 1.10 0.20 1.24 0.20
Mean 83.54 70.11 9.21 83.55 90.79
C.V. % 1.50 1.57 2.17 1.49 0.22
F-value 39.90 33.36 18.90 40.72 18.90
Lack of fit NS NS NS NS NS

X1= WST, X2 = HT and X3 = RT, ***Significant at p<0.001, **Significant at p<0.01, *Significant at p<0.05, NS = Non-significant
Hullability (H)
The mean values of hullability ranged from 59.79% to 75.89 % across different combinations of treatments (Table 6). Table 7 presents the examination of hullability against the selected independent variables, namely water soaking time, hydration temperature, and retention time. A quadratic model was employed to analyze the experimental data, and the statistical significance of linear, quadratic, and interaction effects was determined for each response, as detailed in Table 6. The water soaking time as well as hydration temperature exhibited significantly positive linear (p<0.001) effects on hullability. Furthermore, the negative quadratic effects of water soaking time (p<0.05) and hydration temperature (p<0.01), on hullability were found to be significant, while retention time yielded non-significant results. The tabular data illustrates that increasing water soaking time, hydration temperature and retention time corresponded to increased hullability which is desirable outcome.
Yield loss (YL)
Yield loss for sesame seeds during the dehulling process ranged from 7.77% to 10.04% (Table 6). Table 7 presents the influence of water soaking time, hydration temperature, and dehulling time on yield loss. The response data illustrates a significant increase in yield loss with higher water soaking time, hydration temperature, and retention time. Water soaking time (p<0.001) and hydration temperature (p<0.001), exhibited significant positive linear effects, while the all other influence deemed to be non-significant.
Embryo recovery (ER)
Table 6 represents the impact of water soaking time, hydration temperature, and dehulling time on embryo recovery. The regression coefficients indicate that at the linear level, all independent parameters have a significant positive effect on embryo recovery scores (Table 7). The embryo recovery of sesame seeds ranged from 69.84% to 89.75% (Table 6). The quadratic (p<0.01) effects of water soaking time and hydration temperature show a significant negative effect, while others are non-significant on embryo recovery.
Table 8 shows the suggested model equations for the particular responses. The reasonable agreements were found between adjusted-R2 and predicted-R2 for all the responses. All the parameters showed high adequate precision (>4) and low value of coefficient of variation of the model explained that the experimental results were precise and reliable.

Extraction rate Er(%)
The evaluation of extraction rate influenced by dehulling parameters is detailed in Tables 5 and 6. Regression analysis of data concerning extraction rate during the dehulling process is presented in table, showcasing the impact of water soaking time, hydration temperature, and retention time. The water soaking time (p<0.001) and hydration temperature (p < 0.001) exhibited significant negative individual effects on extraction rate. The extraction rate values of dehulled sesame seed samples ranged from 89.96% to 92.23 % (Table 7).The extraction rate of sesame seeds varied with changes in the independent parameters. The highest extraction rate (92.23%) was achieved with the lowest water soaking time and hydration temperature combination (Table 6).
Table 8 Predictive regression models for responses
Parameters Fitted models R2
DE (%) 86.61 + 5.86X1 + 2.36X2 + 1.19X3 - 0.606X1X2 + 0.766X1X3 - 0.654X2X3 -2.64X1² - 2.27X2² - 1.23X3² 0.97
H (%) 72.79 + 4.60X1 + 1.83X2 + 0.60X3 - 0.532X1X2 + 0.804X1X3 - 0.238X2X3 -1.64X1² - 2.54X2² - 1.19X3² 0.97
YL (%) 9.54 + 0.63X1 + 0.29X2+0.11X3 - 0.0905X1X2 + 0.160X1X3 - 0.038X2X3 - 0.24X1² - 0.25X2² - 0.18X3² 0.94
ER (%) 86.63 + 5.88X1 + 2.32X2 + 1.22X3 - 0.575X1X2 + 0.682X1X3 - 0.693X2X3 - 2.70X1² - 2.27X2² - 1.19X3² 0.97
Er (%) 90.46 - 0.63X1 - 0.29X2 - 0.11X3 + 0.095X1X2 - 0.160X1X3 + 0.038X2X3 + 0.24X1² + 0.25X2² + 0.18X3² 0.94
Table 8 presents the optimization criteria, along with the solution and both predicted and actual response values. The constraints of water soaking time, hydration temperature, and retention time were assigned level 3 importance. The process variables for the best combination of responses (Desirability: 0.72) were determined to be 73.16min. for water soaking time, a hydration temperature of 51°C, and a retention time of 6.20min. Response functions were computed from the final polynomial, resulting in optimized response values of dehulling efficiency (83.02%), hullability (70.05%), yield loss (9.22%), embryo recovery (83.29%), and extraction rate (90.78%).Experimental values and values predicted by the model equations were compared using a t-test, revealing no significant difference between the actual and predicted values (P < 0.05). The closeness between experimental and predicted response values was further confirmed by calculating the percentage coefficient of variation, with values below 5% indicating the suitability of the corresponding models for predicting responses.
Optimisation and Validation
Numerical optimization of independent variable levels was carried out using Design Expert for simultaneous optimization of the responses. The water soaking time of independent variables were kept minimum whereas other in range. Desired goals were assigned for all the parameters for obtaining the numerical optimum values for the responses. Response parameters like dehulling efficiency, hullability, embryo recovery were kept maximum while, others other responses were set in range.
Table 9 Constraints, criteria for optimization, solution along with predicted and actual response values.
Constraints Target Optimized (Predicted) value Experimental value Desirability
Water soaking time (min.) In range 73.16 73.00 0.72
Hydration temperature (°C) In range 50.71 51
Retention time (min.) In range 6.16 6.20
Responses
Dehulling efficiency (%) Maximum 83.32 83.00 ± 0.49
Hullability (%) None 70.05 70.37 ± 0.32
Yield loss (%) None 9.22 9.09 ± 0.12
Embryo recovery (%) None 83.29 82.87 ± 0.42
Extraction rate (%) None 90.78 89.74 ± 0.56

Table 9 demonstrates that experimental values for water soaking time, hydration temperature and retention time closely align with the optimized values, indicating the process step has been optimized. Additionally, the response values are very similar to the predicted ones, further confirming the optimization of the process and at the specified parameters; the results are even more improved.

Table 10: Conclusion

Particular Traditional method Developed methods
Gujarat Til 3 Gujarat Til 4
Water Soaking Time (min.) 120 74.5 73.0
Hydration Temperature (°C) Room Temperature 50 51
Dehulling Time (min.) 6 7 6.20
Dehulling Efficiency (%) 79.29 83.92 83.00
Hullability (%) 68.90 70.11 70.37
Yield loss (%) 1.69 1.61 1.57
Embryo recovery (%) 78.27 83.97 82.87
Extraction rate (ER) (%) 90.16 91.06 89.74

Reduced Soaking Time:

The developed method has a significantly shorter soaking time compared to the traditional method (120 minutes). This reduction in soaking time affects the moisture absorption by sesame seeds, which in turn influences their storage stability. Longer soaking times increase the moisture content in sesame seed, which can accelerate lipid oxidation during storage or processing. Reduced soaking times help minimize moisture absorption, thereby lowering the risk of oxidation and preserving oil stability.

Hydration Temperature
In the developed method, the hydration temperature is raised to 50° to 51°C, allowing for more efficient and faster water absorption despite the reduced soaking time. The higher temperature accelerates the hydration process, leading to better results in dehulling without over soaking, thus improving quality during storage.
Dehulling Efficiency
Higher dehulling efficiency in the developed method indicates that more hulls are removed effectively. Removing hulls is crucial because hulls contain compounds that can degrade during storage, negatively affecting the seeds' quality. Improved dehulling reduces the risk of degradation, contributing to better stability and quality of sesame seeds over time.

Hullability
A slight improvement in hullability in the developed method reflects better separation of hulls, which could result in less retention of moisture and lower chances of microbial activity during storage. This makes the seeds more stable and less prone to spoilage.

Yield Loss
The method demonstrates a lower yield loss, indicating better preservation of the sesame seeds' components (nutritional content, oil, and embryo) even after the dehulling process. This slight reduction in yield loss enhances the seeds' overall quality and longevity during storage.

Embryo Recovery
The higher embryo recovery in the developed method (82.87% for Gujarat Til 3) (83.97% for Gujarat Til 4) means more intact and undamaged seeds, which are less susceptible to degradation during storage. Better embryo recovery indicates that the seeds are in better structural condition, contributing to higher quality retention over time.

Extraction Rate
The higher extraction rate (91.06) in the developed method reflects better recovering the entire kernel of sesame seeds (hulled and unhulled).


Effect on Quality during Storage:
The shorter soaking time in the method reduces the amount of water absorbed by the seeds compared to traditional methods. Lower moisture levels in sesame seeds improve storage stability, as seeds with excess moisture are more prone to spoilage from microbial growth or lipid oxidation. The developed method also removes more hulls effectively (83 % vs 79.29 %)(83.92% vs. 79.29%), enhancing storage stability since hulls can trap moisture and contribute to spoilage during storage, unlike traditional methods. Better hull removal reduces the risk of degradation and ensures a longer shelf life. The higher extraction rate and embryo recovery indicate that sesame seeds retain more oils and nutrients, both of which are crucial for maintaining quality during storage compared to traditional methods. As sesame seed oils are prone to rancidity, the method reduced soaking time helps preserve oil stability for a longer duration. Additionally, the method causes less damage during processing, leading to better quality retention during storage. Lower yield loss means more of the seed's valuable components, like oils and nutrients, are retained, ensuring a longer shelf life and improved nutritional value compared to traditional methods.

The invention has been explained in relation to specific embodiment. It is inferred that the foregoing description is only illustrative of the present invention and it is not intended that the invention be limited or restrictive thereto. All substitution, alterations and modification of the present invention which come within the scope of the following claims are to which the present invention. The scope of the invention should therefore be determined not with reference to the above description but should be determined with reference to appended claims along with full scope of equivalents to which such claims are entitled.
, Claims:We Claim:

1. A hydrothermal assisted dehulling process for varieties of sesame seeds comprises following steps:
i) cleaning of the sesame seeds by removing the foreign materials, damaged, cracked, or scratched seeds;
ii) treating hydrothermally with hot water to soften the hulls of the seeds and making it easier to remove them during dehulling;
iii) removing the surface moisture by drying the seeds using ambient air or by fan as excess moisture affects the dehulling process;
iv) dehulling of the sesame seeds using dehuller to separate them from the kernels;
v) fractioning the dehulled seed mixture to separate based on their size;
vi) collecting the final dehulled sesame seeds.

2. The hydrothermal assisted dehulling process for varieties of sesame seeds as claimed in claim 1, wherein the sesame seeds verities are selected from Gujarat Til 3 and Gujarat Til 4.

3. The hydrothermal assisted dehulling process for varieties of sesame seeds as claimed in claim 1 step (ii), wherein the sesame seeds are immersed in hot water at 50‐55°C for 70 to 75 minutes.

4. The hydrothermal assisted dehulling process for varieties of sesame seeds as claimed in claim 1 step (iv), wherein the sesame seed are dehulled using sesame dehuller for 6 to 8 minutes.

5. The hydrothermal assisted dehulling process for varieties of sesame seeds as claimed in claim 1 step (v), wherein the sesame seed mixture are sieved using an 18 mesh size sieve to separate broken seeds and meal, and 30 mesh size sieve to separate hulls followed by manual separation of the dehulled and unhulled sesame seeds.

Dated this on November 8, 2024

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