Antioxidant degradation kinetics in apples.

The effect of shelf storage under ambient conditions of cut apple dices on degradation of bioactive compounds such ascorbic acid, total phenols, antioxidant activity (% DPPH inhibition) and PPO activity were investigated. The results indicated that antioxidant activity declined significantly over 80 min storage of diced apples at ambient temperature. Similar trend was observed for ascorbic acid, total phenols and PPO activity. Ascorbic acid, total phenols and antioxidant activity degradation followed first-order kinetics where the rate constant (k) was found to be in range for all the thirteen cultivars, though initial ascorbic acid and phenol content varied in different apple cultivars. The reaction rate constant (k) for first order degradation ranged from 1.16 to 1.97, 0.89 to 1.29 and 0.37 to 1.54 for antioxidant activity, total phenols and ascorbic acid, respectively. This explains that antioxidant activity degrades at higher rate than total phenols and ascorbic acid, which also corroborates that antioxidant activity is affected by both total phenols and ascorbic acid content. In general, total antioxidant activity for apple dices kept for 80 min under ambient conditions exhibited lower values as compared to control.

Development of low fat potato chips through microwave processing.

Since snacks high in fats are known to be a significant source of fat and energy intake, these have been put in high dietary restraint category. Therefore, an attempt was made to process potato chips through microwave processing without incorporation of any oil in potato chips. Microwave processing of potato chips was done using microwave power varying from 180 to 600 W using constant sample size. Among eleven different drying models, Parabolic model was found to be the best fit through non-linear regression analysis to illustrate drying kinetics of potato chips. The structural, textural and colour attributes of microwaved potato chips were similar to commercial fried potato chips. It was found that at 600 W after 2.5-3.0 min of processing, potato chips gained the fracturability and crispiness index as that of commercial fried chips. Microwave processing was found suitable for processing of potato chips with low fat content (~3.09 vs 35.5 % in commercial preparation) and with acceptable sensory scores (≥7.6 on 9.0 point on hedonic scale vs 8.0 of control preparation).

Vacuum impregnation: a promising way for mineral fortification in potato porous matrix (potato chips).

Potato chips can be considered as an ideal carrier for targeted nutrient/s delivery as mostly consumed by the vulnerable group (children and teen agers). The present study was planned to fortifiy potato chips with calcium (Calcium lactate) and zinc (Zinc sulphate) using vacuum impregnation technique. At about 70-80 mm Hg vacuum pressure, maximum level of impregnation of both the minerals was achieved. Results showed that after optimization, calcium lactate at 4.81%, zinc sulphate at 0.72%, and vacuum of 33.53 mm Hg with restoration period of 19.52 min can fortify potato chips that can fulfil 10 and 21% need of calcium and zinc, respectively of targeted group (age 4-17 years). The present research work has shown that through this technique, fortification can be done in potato chips which are generally considered as a poor source of minerals. Further to make potato chips more fit to health conscious consumers, rather frying microwaving was done to develop mineral fortified low fat potato chips.

Effect of drying treatments and storage stability on quality characteristics of bael powder.

Dehydration of bael pulp in to powder form is a challenging operation, mainly due to the sticky issue of bael pulp and caking of powder during handling and storage. To overcome on this problem maltodextrin MD (drying aid) and tricalcium phosphate, TCP (anti caking agent) were added to the bael pulp at four levels along with control and dried in a mechanical drier into thin layer at 58 ± 2 °C for 12 h, to obtain a moisture content of 4-5 % in dehydrated pulp. The dehydrated bael pulp was grounded in a laboratory powder mill and sieve with 30 mesh sieve. The powder was packed in 150gauge PP, 400gauge LDPE and 200gauge HDPE pouches and was stored at low temperature (7 °C) and ambient condition (18-35 °C) up to 6 months for storage study. The powder was evaluated for its quality characteristics in respect of acidity, sugars, antioxidant, phenol, ascorbic acid, non- enzymatic browning (NEB) before packaging and during storage. The amount of MD and TCP required to reduce powder stickiness and caking were optimized on the powder properties. The amount of MD (0.25 kg per kg dry bael solids) and TCP (0.15 kg per kg dry bael solids) with the values of degree of caking (19.24 %) and stickiness point temperature (45.4 °C) were found to be optimum for reducing the powder stickiness, caking and nutritional parameters. The adsorption isotherm of bael powder was found to be type-II sigmoid and 200 g HDPE as packaging material followed by storage at low temperature were selected as best process.

Drying kinetics and physico-chemical characteristics of Osmo- dehydrated Mango, Guava and Aonla under different drying conditions.

Mango (Mangiferra indica L), guava (Psiduim guajava L.) slices and aonla (Emblica officinalis L) segments were osmo-dried under four different dying conditions viz., cabinet drier (CD), vacuum oven drier (VOD), low temperature drier (LTD) and solar drier (SD) to evaluate the best drying condition for the fruits. It was found that vacuum oven drying was superior to other mode of drying as it holds maximum nutrients like acidity, ascorbic acid, sugar and water removal and moisture ratio of products. It was found through regression analysis that drying ratio and rehydration ratio was also superior in vacuum drying followed by cabinet drying. In addition, descriptive analysis on sensory score was also found best with vacuum drying while the Non-enzymatic browning (NEB), which is undesirable character on dried product, was more with solar drier.

Recent advances in drying and dehydration of fruits and vegetables: a review.

Fruits and vegetables are dried to enhance storage stability, minimize packaging requirement and reduce transport weight. Preservation of fruits and vegetables through drying based on sun and solar drying techniques which cause poor quality and product contamination. Energy consumption and quality of dried products are critical parameters in the selection of drying process. An optimum drying system for the preparation of quality dehydrated products is cost effective as it shortens the drying time and cause minimum damage to the product. To reduce the energy utilization and operational cost new dimensions came up in drying techniques. Among the technologies osmotic dehydration, vacuum drying, freeze drying, superheated steam drying, heat pump drying and spray drying have great scope for the production of quality dried products and powders.