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20193
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Subject: Food Science and Technology × End date: 2019 × Start date: 2019 ×
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    Assessment of extrusion behaviour of white maize
    (Punjab Agricultural University, Ludhiana, 2019) Arshdeep Singh; Baljit Singh
    The present investigation was undertaken to explore the assessment of extrusion behaviour of white maize and their characterization. Response Surface Methodology (RSM) was used to optimize the extrusion process of white maize based extruded products. Central composite rotator design (CCRD) of response surface methodology was explored to evaluate the effects of independent variables, namely feed moisture content (14-18%), screw speed (400-550) and barrel temperature (125-175℃) on product responses specific mechanical energy (SME), bulk density (BD), water absorption index (WAI), water solubility index (WSI). White maize was subjected to extrusion by co-rotating twin screw extruder at varying processing conditions as per the central composite rotatable design. All the processing conditions had significant impact on product responses. Multiple regression equations were obtained to describe the effects of each variable on product responses. The product responses were most affected by change in feed moisture content, barrel temperature and to lesser extent by screw speed. The negative coefficient of moisture and temperature describes that the value of SME declined with increase of these two variables. Barrel temperature was found to elevate the expansion ratio and water solubility index. Optimization studies resulted in 12.50-16.2 % of feed moisture content, 145℃ of barrel temperature and 360-595 rpm of screw speed as optimum variables to produce acceptable white maize snacks. The products were stored for three months and were found acceptable at the end of three months.
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    ThesisItemOpen Access
    Development of Extruded Products from Glutinous rice (Oryza sativa var. glutinosa)
    (Punjab Agricultural University, Ludhiana, 2019) Lalmuanpuia, C.; Baljit Singh
    The present research work was conducted to explore the utilization of glutinous rice for development of hot and cold extruded products. A screening experiment was conducted for comparison between glutinous and regular non-glutinous varieties of rice for their suitability of for development of hot and cold extruded products including snacks, porridge and pasta. Optimization of the most suitable selected variety for snacks and porridge is conducted using response surface methodology (RSM) at five central composite rotatable design. Experimental design with feed moisture (14-18%), screw speed (400-550 rpm) and barrel temperature (130-170°C) as independent variables produce 20 runs of combinations. The product responses obtained which includes specific mechanical energy (SME), bulk density, expansion ratio, water absorption index (WAI), water solubility index (WSI) and hardness were analysed using RSM to investigate the effect of varying processing conditions. The responses were significantly affected by changes in the processing condition. The optimised processing conditions for development of extruded snacks were 14 – 15.5 % feed moisture, 445 - 550 rpm screw speed at optimum barrel temperature of 1460C. And the optimised processing conditions for development of porridge were 14 – 14.8 % feed moisture, 470- 495 rpm screw speed at optimum barrel temperature of 1400C. Validation of the model and its adequacy in predicting optimum processing conditions was proven by comparing the predicted values of responses given by the model and the actual values obtained, which do not have variation more than 5% proving validity of the model. Glutinous rice based pasta with acceptable cooking quality can be produced by supplementation with xanthan gum (2%), vital gluten (6%) and pre-gelatinized flour from high amylose varieties (30%). The optimized extruded snacks and porridge were kept for storage studies and are found to be acceptable till the six months period. However, there were slight increase in moisture content, water activity, hardness and minute changes in the color of the stored samples. Glutinous rice containing low amylose resulted in superior expansion which is more desirable in expanded extruded snacks and porridge.
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    ThesisItemOpen Access
    Utilization of lemongrass for shelf life extension and flavor enhancement of cookies
    (Punjab Agricultural University, Ludhiana, 2019) Amandeep Kaur; Amarjeet Kaur
    Study was carried out on “Utilization of lemongrass for shelf life extension and flavor enhancement of cookies”. Lemongrass was procured from department of Agronomy, washed, sliced and dried at two temperatures i.e. 35 and 500C for 16-18 hrs. Drying temperature which was selected was 500C for 16-18 hours. Lemongrass was ground into powder and analyzed for proximate composition, total phenols and phytochemicals. It was found to contain 8.1% moisture, 9.01% ash, 1.31% fat, 8.6% protein, 7.36% fibre and 65.28% carbohydrates. Total phenol content of powder was 0.13 g/100g as GAE gallic acid equivalent and flavonoids ranged from 0.49 g/100 g powder. The powder was incorporated in cookies at 0, 2.5% and 5% levels. Cookies containing 2.5% of lemongrass powder were found best on sensory evaluation scores. Cookies were stored in high density polyethylene (HDPE) for a period of 6 months. During this period changes in free fatty acid (FFA), moisture content, water activity (aw) and peroxide value (PV) were recorded. Although there was non significant increase in these constituents but cookies were found acceptable only upto 2 months organoleptically. The estimated cost for the cookies was Rs. 211.21/kg and Rs. 211.71/kg, respectively for 2.5 and 5% level of lemongrass incorporation as compared to Rs.210.71/kg for the control.