A. S. Bawa

Utilization of byproducts and waste materials from meat, poultry and fish processing industries: a review

India is bestowed with vast livestock wealth and it is growing at the rate of 6% per annum. The contribution of livestock industry including poultry and fish is increasing substantially in GDP of country which accounts for >40% of total agricultural sector and >12% of GDP. This contribution would have been much greater had the animal by-products been also efficiently utilized. Efficient utilization of by-products has direct impact on the economy and environmental pollution of the country. Non-utilization or under utilization of by-products not only lead to loss of potential revenues but also lead to the added and increasing cost of disposal of these products. Non-utilization of animal by-products in a proper way may create major aesthetic and catastrophic health problems. Besides pollution and hazard aspects, in many cases meat, poultry and fish processing wastes have a potential for recycling raw materials or for conversion into useful products of higher value. Traditions, culture and religion are often important when a meat by-product is being utilized for food. Regulatory requirements are also important because many countries restrict the use of meat by-products for reasons of food safety and quality. By-products such as blood, liver, lung, kidney, brains, spleen and tripe has good nutritive value. Medicinal and pharmaceutical uses of by-product are also highlighted in this review. Waste products from the poultry processing and egg production industries must be efficiently dealt with as the growth of these industries depends largely on waste management. Treated fish waste has found many applications among with which the most important are animal feed, biodiesel/biogas, dietectic products (chitosan), natural pigments (after extraction) and cosmetics (collagen). Available information pertaining to the utilization of by-products and waste materials from meat, poultry and fish and their processing industries has been reviewed here.

Genetically modified foods: safety, risks and public concerns—a review

Genetic modification is a special set of gene technology that alters the genetic machinery of such living organisms as animals, plants or microorganisms. Combining genes from different organisms is known as recombinant DNA technology and the resulting organism is said to be ‘Genetically modified (GM)’, ‘Genetically engineered’ or ‘Transgenic’. The principal transgenic crops grown commercially in field are herbicide and insecticide resistant soybeans, corn, cotton and canola. Other crops grown commercially and/or field-tested are sweet potato resistant to a virus that could destroy most of the African harvest, rice with increased iron and vitamins that may alleviate chronic malnutrition in Asian countries and a variety of plants that are able to survive weather extremes. There are bananas that produce human vaccines against infectious diseases such as hepatitis B, fish that mature more quickly, fruit and nut trees that yield years earlier and plants that produce new plastics with unique properties. Technologies for genetically modifying foods offer dramatic promise for meeting some areas of greatest challenge for the 21st century. Like all new technologies, they also pose some risks, both known and unknown. Controversies and public concern surrounding GM foods and crops commonly focus on human and environmental safety, labelling and consumer choice, intellectual property rights, ethics, food security, poverty reduction and environmental conservation. With this new technology on gene manipulation what are the risks of “tampering with Mother Nature”?, what effects will this have on the environment?, what are the health concerns that consumers should be aware of? and is recombinant technology really beneficial? This review will also address some major concerns about the safety, environmental and ecological risks and health hazards involved with GM foods and recombinant technology.

Effect of Pretreatments on Drying and Rehydration Kinetics and Color of Sweet Potato Slices

The effect of air temperature and pretreatments (KMS: citric acid) on drying kinetics of sweet potato slices was investigated. Drying experiments were performed in a tray dryer. In falling rate period, moisture transfer from sweet potato slices was described by applying the unsteady-state Fickian diffusion model, and the rate constant (k) were calculated. The effect of temperature on k could be interpreted according to Arrhenius law. Drying rate and therefore k values were found to be affected by pretreatments. Rehydration rates of dried sweet potato slices at 25, 40, 80°C were also determined and found to be independent of drying conditions and rehydration temperature. The ΔE value was found to be the highest for slices treated at 50°C with 0.5:1.0% KMS and citric acid.

Technology, applications and modelling of ohmic heating: a review

Ohmic heating or Joule heating has immense potential for achieving rapid and uniform heating in foods, providing microbiologically safe and high quality foods. This review discusses the technology behind ohmic heating, the current applications and thermal modeling of the process. The success of ohmic heating depends on the rate of heat generation in the system, the electrical conductivity of the food, electrical field strength, residence time and the method by which the food flows through the system. Ohmic heating is appropriate for processing of particulate and protein rich foods. A vast amount of work is still necessary to understand food properties in order to refine system design and maximize performance of this technology in the field of packaged foods and space food product development. Various economic studies will also play an important role in understanding the overall cost and viability of commercial application of this technology in food processing. Some of the demerits of the technology are also discussed.

Development of ginger based ready-to-eat appetizers by response surface methodology.

Ginger is an herbaceous perennial rhizome traditionally used in culinary for its flavor and pungency. It is also used as carminative, stimulant and for its anti-emetic properties due to gingerols and shogaols. Appetite loss is one of the problems faced at high altitudes and the appetizers based on ginger may be useful for appetite stimulation. The fruit munch and ginger munch based on fresh and powdered ginger respectively were developed using response surface methodology (RSM). The sensory score, acidity and total sugars were the responses in the central composite designs of experiments with three independent variables. The ingredients raisins, dates, almonds were pre-processed by frying in stable fat while juice was extracted from pseudolemon and lemon. The optimized composition of ingredients was processed further through concentration. The carbohydrate rich munches had vitamin C content in the range 37-43mg/100g and calorific value of about 90kCal per munch. The munches packed in metalized polyester pouches had a shelf life of 8 months at ambient conditions (18-33 degrees C) as well as at a fixed temperature of 37 degrees C storage.

Effect of fiber incorporation on rheological and chapati making quality of wheat flour

Traditional Indian unleavened bread (chapati) was prepared by incorporating wheat bran (insoluble fiber) and oat bran (soluble fiber) at different levels into whole wheat flour. Central composite rotatable design with 2 independent variables (wheat bran and oat bran) at 5 levels (wheat bran 3–9, oat bran 6–12%) was used to design the experiments. The flour samples containing different concentration of bran were analysed for pasting and mixing characteristics. Wheat bran had a negative (p ≤ 0.05) effect on peak viscosity, break down and final viscosity, whereas oat bran had a positive (p ≤ 0.05) effect on set back and final viscosity. Among mixing characteristics, the peak value was negatively affected (p ≤ 0.05) with increase in the level of both variables. Both variables had positive (p ≤ 0.05) effect on hardness of chapati while the cohesiveness, chewiness and overall acceptability scores were negatively affected. Based on compromise optimization, it is recommended to incorporate 5.5 g wheat bran and 9.7 g oat bran per 100 g flour for making optimally acceptable fiber rich chapati.

Development and Evaluation of Long Shelf-Life Ambient Stable Chapaties Without The Use of Chemical Preservatives

Convenient, ready-to consume thermally processed chapaties with natural sensory attributes were developed. Chapaties were packed in indigenously developed retortable pouches and processed in an air-steam retort. The time-temperature history was recorded during heat processing using an Ellab data cum F o recorder . The total processing time was 20min with a F o value of 3.0. Chapaties remained stable and acceptable even after storage for one year under ambient temperature (15-35°C) conditions. During storage, chemical parameters like peroxide, thiobarbituric acid and free fatty acid values increased with concomitant decrease in sensory score. After 12 months of storage, the overall acceptability score of chapaties decreased significantly (p≤0.05) from 8.5 to 7.2 on a 9 point hedonic scale with an increase in peroxide and free fatty acid values from 4.94 to 15.10 meqO 2 /kg fat and 0.46 to 1.79 % oleic acid respectively. Microbiologically chapaties were found to be safe during entire period of storage.

Effects of Osmotic Agents on Colour, Textural, Structural, Thermal, and Sensory Properties of Apple Slices

Effects of various osmotic agents (i.e., glucose, fructose, sucrose, maltose, sorbitol, and honey) were evaluated in terms of moisture loss and solid gain besides objective measurements of colour, texture, glass transition temperature; subjective sensory profile; and scanning electron microscopic cellular structure of osmotically dehydrated apple slices. Significantly (p < 0.05) higher solid gains were observed in the samples dipped in glucose and fructose solutions, whereas maltose-treated samples showed higher water loss. The glass transition temperatures varied from −68.4 to −45.6°C, minimum in the case of glucose and maximum in maltose-treated ones. The sucrose- and maltose-treated samples had significantly (p < 0.05) higher L* showing restricted browning. The a* value was maximum and minimum in the case of sucrose- and fructose-treated samples, respectively. Hardness was found to be significantly (p < 0.05) higher (20.104 N) in sucrose-treated samples, while it was at a minimum (4.441 N) in sorbitol-treated ones. The scanning electron microscope studies revealed that cellular structure was retained in sucrose-treated samples, while the damage was observed to be more in the glucose- and fructose-treated ones. The sensory attributes of the osmo-dehydrated samples were found to be better in the case of sucrose-treated samples. The type of humectant, in terms of molecular size, significantly influences the mass transfer process that could be optimized to make the process versatile to meet the requirements of processors and consumers.

Simplification and optimization of deMan Rogosa Sharpe (MRS) medium for enhanced production of bacteriocin by Weissella paramesenteroides DFR-8.

Complex growth medium such as deMan Rogosa Sharpe (MRS) medium, commonly used for cultivation of fastidious lactic acid bacteria (LAB) interfere in bacteriocin purification. Sometimes all the ingredients of a defined medium are not required by all LAB strains for bacteriocin production. In the present study, composition of the MRS medium for the production of bacteriocin by Weissella paramesenteroides DFR-8, an isolate from cucumber (Cucumis sativus), was simplified and optimized with a step-wise strategy. In the first step, production profile, effect of incubation temperature, various C and N sources were investigated. In the second step, central composite rotatable design was employed to decide the optimal concentration of 3 key components (glucose, tryptone and pH) and the experimental results were fitted with a second order polynomial regression equation. According to the set criteria, the predicted bacteriocin titer from a medium containing 7.99% glucose, 9% tryptone, pH 7.5 (91.9% desirability) was 540 AU/ml and the observed bacteriocin titer was 538 AU/ml that indicated the validity of the developed model. Using optimized medium, bacteriocin titer of 674.5 AU/ml could be achieved after 72 h of fermentation that is nearly 2.5 fold higher than that obtained from unmodified MRS medium.

Effect of Vacuum Frying on Changes in Quality Attributes of Jackfruit (Artocarpus heterophyllus) Bulb Slices

The effect of frying temperatures and durations on the quality of vacuum fried jackfruit (JF) chips was evaluated. Moisture content and breaking force of JF chips decreased with increase in frying temperature and time during vacuum frying whereas the oil content increased. The frying time for JF chips was found to be 30, 25, and 20 minutes at 80, 90, and 100°C, respectively. JF chips fried at higher temperature resulted in maximum shrinkage (48%). The lightness in terms of hunter L * value decreased significantly (P < 0.05) during frying. Sensory evaluation showed maximum acceptability for JF chips fried at 90°C for 25 min. Frying under vacuum at lower temperatures was found to retain bioactive compounds such as total phenolics, total flavonoids, and total carotenoids in JF chips. Almost 90% of carotenoids were lost from the samples after 30 min of frying at 100°C.