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Keeping in view the diabetes status that has affected about 415 million people globally and is the leading cause of death in many countries along with therising demand for low Glycemic Index (GI) foods, the purpose of this paper is to optimize the extrusion process for the development of low GI snacks from underutilized crops like water chestnut and barley.

The extrusion parameters (screw speed and barrel temperature), feed moisture and water chestnut flour, barley flour proportion, were varied and their effects on system and product responses (specific mechanical energy, water absorption index, water solubility index, bulk density, expansion ratio and breaking strength) were studied.

All the system and product responses were significantly affected by independent variables. Response surface and regression models were established to determine the responses as function of process variables. Models obtained were highly significant with high coefficient of determination (R²=0.88). The optimum processing conditions obtained by numerical optimization for the development of snacks were 90°C barrel temperature, 300 rpm screw speed, 14 per cent feed moisture and WCF-to-BF ratio as 90:10. Shelf life studies confirmed that the developed snacks can be safely stored in HDPE bags for a period of six months under ambient conditions.

Water chestnut and barley flour did not blend till date for extrusion cooking. Such snacks shall be a viable food option for diabetic people and can act as laxative due to high fibre and β-glucan content from barley.

Snack industry is one of the fastest growing food sectors globally, and people are nowadays conscious about intake of healthy snacks on regular basis. There is enormous variety of ready-to-snacks available in the market. Brown rice though highly nutritious in comparison to polished rice is consumed meagerly by masses. Each raw material/ingredient used in extrusion cooking requires specific control of processing variables to meet acceptable product characteristics and consumer demands, which in turn necessitates the need to optimize the conditions for development of brown-rice-based snacks. The aim of this study was to optimize the extrusion cooking conditions for development of brown-rice-based extrudates.

Extrusion conditions were optimized through design expert using central composite rotatable design (CCRD) experimental design. The effect of feed moisture (10–22%), screw speed (215–385 rpm) and barrel temperature (95–160 °C) on specific mechanical energy (SME), bulk density (BD), water absorption index (WAI), water solubility index (WSI), expansion ratio (ER), breaking strength (BS) and instrumental color (L*, a*, b*) was evaluated.

All the system and product responses were significantly (p < 0.01) affected by independent variables. Regression models obtained were highly significant with high coefficient of determination (R² = 0.992). The optimum extrusion conditions obtained by numerical optimization for development of snacks were moisture content of 12%, screw speed of 350 rpm and temperature of 133 °C. The vitamin B₁ content of brown-rice-based snacks was 0.45 mg/100 (50% of RDA) whereas no vitamin B₁ was detected in white-rice-based snacks used as control.

The developed snacks contain 0.45 mg/100 g of vitamin B₁. If a person on an average consumes 150 g of snacks in a day, 50% of RDA (1.2 mg/day) for vitamin B₁ can be sufficed. Therefore, developed snacks can prove to be a viable vehicle to reduce the vitamin B₁ deficiency burden among the target population. Large-scale production and consumption of such type of snacks could improve the nutritional status of vitamin B1 deficient people. Furthermore, it can also provide a good opportunity for snack industry to develop nutritious snacks through utilization of brown rice.

Brown rice flour contains nutrients such as iron, calcium, zinc, sodium and vitamin B₁ in appreciable portions and was thus explored for development of nutritious snacks. Moreover, developed snacks recorded an overall acceptability of 4.70 out of 5, which depicts it is acceptable for mass production and consumption.

Low glycemic index gluten-free cookies from high amylose rice flour were prepared by modifying baking conditions and ingredient composition.

Baking temperature, baking time, and concentration of carboxymethyl cellulose (CMC) were varied between 170 and 190° C, 12–25 min, and 0.2–1%, respectively, using central composite rotatable design. The developed cookies were packed in metalized polyester pouches and stored under ambient conditions for a period of 90 days.

Width and bulk density of cookies increased significantly (p < 0.05) with an increase in baking temperature, while thickness, baking loss and yield decreased with an increase in baking temperature. Puffiness increased predominantly with the increase in the concentration of CMC. Design expert predicted baking temperature of 185° C, baking time of 22 min, and 0.8% concentration of CMC as desirable conditions for the development of gluten-free cookies from rice flour. Cookies developed after following optimized conditions recorded dietary fiber of 4.66%, resistant starch (RS) content of 7.20% and predicted glycemic index (pGI) of 44.60. RS, pGI, moisture, water activity, free fatty acids and peroxide value increased significantly, whereas hardness and overall acceptability decreased during storage.

Gluten-free (GF) foods are in high demand globally due to the prevalence of celiac disease. Rice lacks gluten protein, and thus, can serve as a potential raw material for the development of GF cookies. In the present study, the ingredient modification and freezing interventions during baking were found to be crucial if the development of low GI gluten-free cookies having good RS content is targeted. Optimized GF cookies prepared via technological intervention and packed in metalized polyester were shelf stable for up to 3 months under ambient conditions. Furthermore, resistant starch content was enhanced while the predicted glycemic index was decreased during storage. Adoption of baking conditions and CMC level optimized in the present study can help to develop shelf-stable GF bakery products for people suffering from comorbidities like celiac disease and diabetes.

Resistant starch content was enhanced while predicted glycemic index was decreased during storage of gluten-free cookies prepared from high amylose rice flour. The developed cookies can be a complementary diet to people suffering from comorbidities like celiac disease and diabetes.

This study aims to develop sweet chestnut incorporated corn-based extrudates by the optimization of process conditions.

The independent process variables for extrusion (blend ratio, barrel temperature, screw speed and feed moisture) were investigated to govern their impact on reliant variables, namely, bulk density, specific mechanical energy, water absorption index, water solubility index, color and hardness. Product and system responses were significantly (p < 0.05) affected by the independent variables. Experimental design with quadratic models experienced a high coefficient of determination (R² = 0.99).

Numerical optimization for the development of extrudates resulted in optimum conditions having corn flour: sweet chestnut flour (80:20), barrel temperature (120°C), screw speed (340 rpm) and feed moisture (12%). Fat, moisture and protein contents of the developed extrudates using optimum conditions were significantly (p < 0.05) lower compared to raw materials – corn and sweet chestnut. The packaging of extrudates in aluminum laminates revealed shelf stability of three months at room temperature without deterioration of quality.

Nutritionally rich sweet chestnut extruded products would be an exclusive option to already existing snacks in the market and can facilitate a new sphere in extruded product sector.

The present research was envisaged with an aim to optimize the system and the product responses for the development of tomato pomace-incorporated corn-based extrudates employing central composite rotatable design and determine its proximate, lycopene, consumer acceptability and storage studies.

Lycopene-rich extrudates were developed from corn flour blended with different levels of tomato pomace. The independent extrusion variables, namely, feed composition (95:5 to 75:25), feed moisture (12–20%), screw speed (200–600 rpm) and barrel temperature (125–185 °C), were studied to determine their influence on dependent variables, namely, specific mechanical energy, hardness, water solubility index, lateral expansion, water absorption index, bulk density and color.

All of the quality parameters were significantly (p < 0.05) influenced by independent variables. The regression models obtained for all the responses showed high coefficients of determination (R2 = 0.85–0.95). The optimum conditions for the development of tomato pomace-incorporated corn-based extrudates were feed composition (90:10), feed moisture (14%), screw speed (300 rpm) and barrel temperature (170 °C). The moisture, fat and carbohydrate contents of the extrudates were significantly reduced, whereas protein, ash and fiber were significantly (p < 0.05) enhanced after the incorporation of tomato pomace. Aluminum laminates were found to be the suitable packaging materials for extrudates for a period of 120 days in comparison to high-density polyethylene packages.

As far as the authors could possibly know, scanty literature exists wherein the tomato pomace has been utilized for the development of lycopene-rich corn-based extruded snacks. Such extrudates with significantly higher fiber and lycopene contents than corn flour will serve as a suitable alternative for the development of shelf-stable ready-to-eat extruded snacks.

The purpose of this article was to highlight the various methods of extrusion technologies for encapsulation of bioactive components (BACs).

BACs provide numerous health-care benefits; however, downsides, including a strong effect of organoleptic properties by reason of the bitterness and acridity of a few components, and also a short shelf-life, limit their application in food. The food industry is still demanding complicated qualities from food ingredients, which were often impossible to obtain without encapsulation such as stability, delayed release, thermal protection and an acceptable sensory profile. Various techniques such as melt injection extrusion, hot-melt extrusion, electrostatic extrusion, co-extrusion and particles from gas-saturated solutions, could be used for maintaining these characteristics.

Extrusion technology has been well used for encapsulation of bioactive chemicals in an effort to avoid their numerous downsides and to boost their use in food. The count of BACs that could be encapsulated has risen owing to the extrusion technology just as form of encapsulation. Extrusion technique also aids in the devaluation of the fragment size of encapsulated BACs, allowing for greater application in the food business.

The study reported that encapsulating BACs makes them more stable in both the product itself and in the gastrointestinal tract, so using encapsulated BACs would result in a product with stronger preventive properties.

The purpose of the present study was to develop low Glycemic Index (GI) crackers from water chestnut flour (WCF) and barley flour (BF).

Five blends were prepared by mixing WCF with BF in the proportion of 100:0, 70:30, 50:50, 30:70 and 0:100, respectively. The baking process as well as ingredients were modified for the production of low GI crackers.

BF incorporation had significant (p < 0.05) effect on physical characteristics, organoleptic attributes and glycemic response of crackers. The resistant starch content of final product was found to be higher than WCF and BF. The research confirmed that replacement of 30 percent WCF with BF is feasible for development of low GI crackers with desired sensory attributes. The inference drawn from storage studies was that the developed crackers can be stored safely (with an overall acceptability score of greater than three on a 5-point scale) in metallized polyethylene up to 35 days under refrigerated conditions and 28 days under ambient conditions.

Although low GI crackers were developed successfully from WCF and BF in the present study. However, detailed storage studies of such crackers can be done in future so as to perform the tests of type-intensity and temporal dominance of sensation. Also, in view of their low GI, these crops need to be evaluated in future for development of other bakery products like bread, cake, muffins, etc.

Water chestnut and barley despite having good nutritional profile and low GI are still considered as underutilized crops. In the present study, these crops were explored for development of low GI crackers especially for people suffering from diabetes. The outcome of this study will open up a new window in the baking sector to develop low GI crackers viz-a-viz will add value to these crops which will help to provide remunerative returns to those who are directly or indirectly involved in trade of these underutilized crops.

This was the first reported innovative attempt to develop low GI crackers from WCF and BF. For development of crackers having desired sensory characteristics, it was found feasible to blend WCF and BF in the ratio of 70:30.

Currently, there is a great demand for those food products that are easy to prepare or ready for direct consumption. Making pear fruit/juice available round the year is desirous owing to pears' high-nutritional value and specific pleasant taste. Pear is, however, a seasonal fruit and under ambient conditions has a limited shelf life rendering it available as fresh fruit for a specific period.

The study aimed to optimize the spray drying process parameters using response surface methodology for the development of pear juice powder. The process variables included the inlet air temperature of 140–210°C, maltodextrin levels of 4–25%, atomization speed of 11,400–28,000 rpm, feed flow rate of 180–630 mL/hr, and feed total soluble solids (TSS) of 13–30°Brix. The dependent responses were powder yield, solubility, antioxidant activity {% 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity}, dispersibility, hygroscopicity and particle density.

Among independent variables, inlet air temperature showed a predominant effect. The optimum processing conditions for the development of pear juice powder with optimum quality were 163.02°C inlet air temperature, 13.50% maltodextrin, 28,000 rpm atomization speed, 390.94 mL/h feed flow rate, and 25.5°Brix feed TSS. Under these optimum conditions, pear powder with desirable properties could be produced. The experimental and predicted values were found to be in agreement, indicating the suitability of the model in predicting optimizing responses of pear powder. Glass transition temperature of pear powder was found to be 36.60 ± 0.40°C, which is much higher than that of ambient temperature, suggesting better shelf stability.

The processing of pear fruit has resulted in the increased demand for pear juice powder in both domestic and international markets as a primer of new food products. The optimum conditions obtained in the current study could provide a new insight to the food industry in developing spray-dried pear powder of optimum quality. This can open up a new horizon in the field of food industry for the common masses of Jammu and Kashmir, India.

The purpose of this study was to formulate a complete protein food from lentil flour (LF) and egg powder (EP) through microwave-assisted extrusion technology.

In the first part of the hybrid technology, the feed proportion and extrusion conditions were optimized through design expert using central composite rotatable design. In the second part of hybrid technology, the optimized protein pellets (PP) obtained were subjected to microwave heating (MH) for 50,100, 150, 200 and 250 s.

The optimum predicted conditions for development of pellets using extrusion cooking were feed proportion (85% LF and 15% EP), barrel temperature (140°C), screw speed (340 rpm) and feed moisture content (12%). When these pellets were subjected to MH, 150 s of heating time was considered as prudential to induce desirable quality changes in PP. The increase in sectional expansion index, crispness and overall acceptability from 0.637 to 0.659, 4.51 to 6.1 and 3.27 to 3.59 with corresponding decrease in bulk density and breaking strength from 73.33 to 69.75 kg/cm³ and 6.24 to 5.13 N during 150 s of MH indicated that quality characteristics of extruded PPs were improved after MH.

Nowadays, consumers have become more health conscious than ever, and the demand for nutritious snacks has increased many folds. However, the high protein content restricts expansion of snacks, which was overcome by subjecting extruded pellets to MH to produce third generation pellets. Furthermore, the PP has a protein content of 31.62%, which indicates that if an average person consumes 100 g of these snacks, it will suffice 60% of total recommended dietary intake (0.75 g/kg body weight/day). Lentil-based pellets expanded by use of such hybrid technology (microwave-assisted extrusion cooking) can help to provide a feasible, low cost and protein-rich diet for malnourished population besides being a value addition to lentils.

LF in combination with EP was tested for the first time for development of nutrient dense pellets. Moreover, use of microwave-assisted extrusion cooking offers a workable and innovative technique of developing protein-rich pellets with improved physico-chemical and sensory attributes.

Apricots are not only nutritionally-rich but also possess pharmacological significance owing to their high antioxidant activity, and they are rich in vitamins, fibers, bioactive phytochemicals and minerals. Because of its immense organoleptic characteristics, apricot juice (AJ) is well accepted; however, it has a limited shelf-life, thereby demanding it to be converted into other shelf-stable form. One of the approaches is converting this juice into dehydrated powder. Amongst the various dehydration techniques available, spray drying is usually preferred; however, it involves the use of several independent variables, which need to be optimized, thus prompting to optimize the process to obtain spray dried apricot powder (SDAP) with improved quality.

The spray-drying process of apricot juice was done using the response surface approach. The process variables included the inlet air temperature of 135–220°C, gum arabic concentration of 4–25%, feed flow rate of 124–730 mL/h, feed total soluble solids (TSS) of 10-30°Brix and atomization speed of 11,400–28,000 rpm. The dependent responses were powder yield, hygroscopicity, solubility, moisture content, carotenoids (CT), ascorbic acid (AA), radical scavenging activity (RSA), lightness, wettability, bulk density, particle density and porosity.

Amongst all independent variables, inlet air temperature had most predominant impact on all the investigated responses. The optimum processing conditions for development of apricot powder with optimum quality were 190°C inlet air temperature, 18.99% gum arabic, 300.05 mL/h feed flow rate, 24°Brix feed TSS and 17433.41 rpm atomization speed. The experimental values were found to be in agreement with the predicted values, indicating the suitability of models in predicting optimizing responses of apricot powder. Flowability as Carr's index (CI) (22.36 ± 1.01%) suggests fair flow of powder. Glass transition temperature of powder was 57.85 ± 2.03°C, which is much higher than that of ambient, suggesting its better shelf stability.

To the best of author's knowledge, very limited or very few studies have been carried out on the spray-drying process for the manufacture of SDAP. The results of this investigation will open up new horizons in the field of food industry in the Union Territory of Jammu and Kashmir, India or elsewhere in the apricot-growing areas of India.