P. S. Raju

Instrumental Textural Changes in Banana (Var. Pachbale) During Ripening Under Active and Passive Modified Atmosphere

Textural properties of modified atmosphere packaged banana (var. Pachbale), stored at 13 ± 1°C, followed by ethrel induced ripening at 30 ± 1°C were studied. Modified atmosphere included active as well as passive types involving flushing of polyethylene pouches (100 gauge) with specific gas mixture (3% O2 + 5% CO2 + 92% N2) at partial vacuum (52.63 kPa), respectively. The MAP applications resulted in varied response of various textural parameters including penetration, shear, force-relaxation, and instrumental texture profile analysis. All the parameters showed a decline except adhesiveness with the progress in ripening. Both the gas flushed, as well as passive MAP stored samples, followed a trend similar to that for control ones, however, the partial vacuum packaged bananas showed persistence of overall texture followed by normal ripening under ethrel induction. The ripened fruits from all the three types of MAP applications did not show any impediment to the instrumental textural quality. In the case of partial vacuum packaged samples, a threshold low temperature duration of 30 days was found to be optimal to avoid abnormal ripening in terms of texture. The instrumental textural kinetic for TPA parameters was found to follow linear model for a longer duration of the storage at low temperature (13 ± 1°C) with high correlation coefficients ranging from 0.845 to 0.989.

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.

Effect of Controlled Atmosphere Storage and Chitosan Coating on Quality of Fresh-Cut Jackfruit Bulbs

Fresh-cut jackfruit bulbs were evaluated for quality changes as effect of an additive pretreatment with CaCl2, ascorbic acid, citric acid, and sodium benzoate followed by chitosan coating. Different types of samples such as pretreated and coated, only pretreated, only coated, and untreated were subjected to controlled atmosphere (CA) storage (3xa0kPa O2u2009+u20096 or 3xa0kPa CO2; N2 balance) or normal air at 6xa0°C. CA conditions, pretreatment, as well as chitosan coating in synergy with each other, could significantly minimize the loss in total phenolics and ascorbic acid content of the samples to the levels of around 5% and 17%, respectively, during extended storage up to 50xa0days. Chitosan coating could also restrict the changes in microbial load. The CA condition of 3xa0kPa O2u2009+u20096xa0kPa CO2 was found to render higher efficacy in retaining quality attributes of the samples.

Efficacy of Aqueous Ozone and Chlorine in Combination with Passive Modified Atmosphere Packaging on the Postharvest Shelf-Life Extension of Green Chillies (Capsicum annuum L.)

Aqueous ozone and chlorine treatments were evaluated for their effectiveness on postharvest quality of green chillies packed under passive modified atmosphere (MA) conditions. Ozone (30xa0mg) treatment was found significantly (pu2009>u20090.05) more effective in maintaining the postharvest quality of chillies as compared to chlorine-treated (100xa0mgxa0kg−1) and untreated samples. Use of passive modified atmospheric packaging further maintained the quality of chillies and increased their shelf-life when stored at (8u2009±u20091xa0°C). Ozone washing also delayed senescence and maintained firmness of chillies during storage. The results suggest that microbial population in terms of total plate count, coliforms, as well as yeast and mold counts of fresh green chillies can be reduced without depleting its major bioactive compounds except for ascorbic acid using combined treatments of ozone wash and modified atmosphere packaging (MAP). This combination treatment (ozoneu2009+u2009MAP) also maintained pigment stability in chillies during storage and extended the shelf-life up to 36xa0days against 28 and 22xa0days in the case of chlorine-washed and untreated samples, respectively.

Kinetics of moisture loss and oil uptake during deep fat frying of Gethi (Dioscorea kamoonensis Kunth) strips

Investigation was carried out to study kinetics of moisture loss, oil uptake and tristimulus colour during deep fat frying of Gethi (Dioscorea kamoonensis kunth) strips. Deep fat frying of Gethi strips of size 6 × 6 × 40xa0mm was carried out in a laboratory scale fryer at different temperatures ranging from 120 to 180xa0°C. The investigation showed that the moisture loss and oil uptake followed the first order kinetics equation (ru2009>u20090.95, pu2009<u20090.05). The kinetic coefficients for moisture loss and oil uptake increased significantly (pu2009<u20090.05) with temperature from 0.166 to 0.889xa0min-1 and 0.139 to 0.430xa0min-1 respectively. The temperature dependency of rate constants for moisture loss and oil uptake values was described using Arrhenius equation (ru2009>u20090.99, pu2009<u20090.01). The activation energies for moisture loss and oil uptake were found to be 41.53xa0KJ/mol and 27.12xa0KJ/mol respectively. The hunter colour parameters were significantly affected by frying temperature and frying time. The hunter lightness (L) value increased with respect to frying time initially, followed by decline and same trend was observed at higher temperatures of frying with elevated rate, whereas hunter redness (a) value increased significantly (pu2009<u20090.01) with time as well as temperature of frying and obeyed zero order rate equation. The temperature dependency kinetic coefficients of Hunter (a) value were described by Arrhenius equation and the energy of activation for change in hunter redness was found to be 42.41xa0KJ/mol (ru2009>u20090.99, pu2009<u20090.01). The other hunter colour parameters such as chroma, hue angle and total colour difference were markedly affected by frying temperature as well as frying time.

Nondestructive Monitoring of Ripeness in Mango Cultivars by Acoustic Resonance Spectroscopy

Mango cultivars, i.e. Neelam, Alphonso, Banganapalli, Totapuri, and Mallige were subjected to acoustic resonance spectroscopy at unripe, semi-ripe, and ripe stages, as well as in case of ripe bruised fruits. The Neelam variety of mango was screened for internal infestation by means of acoustic spectroscopy. Acoustic data on dominant and first frequencies, damping ratio, and firmness indices were obtained and correlated with mechanical penetration tests as well as a/b values of the tristimulus color profile. The correlations between mechanical tests and acoustic parameters varied from 0.81 to 0.933. However, damping ratio and dominant frequency along with firmness index showed a better correlation with penetration test vis-à-vis first frequencies. The correlations between acoustic parameters and a/b tristimulus color values showed lesser extent and significance of correlations ranging from 0.416 to 0.667. The correlations were found to be positive or negative depending on the specific acoustic parameters. However, in the case of internally infested Neelam, the drop in the first frequency was found to be a significant acoustic indicator. Nondestructive quality monitoring by acoustic spectroscopy was found as such to be consistent as far as the tissue softening and bruising are concerned.

Utilization of Tender Coconut Pulp for Jam Making and Its Quality Evaluation During Storage

An attempt was made to utilize the residual coconut pulp left in the tender coconuts after removal of coconut water. The coconut pulp was mixed with pineapple pulp in different proportions to increase the acceptability of the jam. An increase in the level of coconut pulp was found to significantly (pu2009<u20090.05) increase the fat content as well as Na, K, and Ca contents in the jam. Texture profile analysis revealed a significant (pu2009<u20090.05) decrease in hardness whereas adhesiveness, springiness, cohesiveness, gumminess, and chewiness increased significantly (pu2009<u20090.05) with an increase in the level of coconut pulp in the jam affecting its setting quality. The L* and a* values were found to increase significantly (pu2009<u20090.05), whereas b* values decreased significantly (pu2009<u20090.05) with an increase in the tender coconut pulp level. The jam containing 75xa0% tender coconut pulp and 25xa0% pineapple pulp showed a maximum sensory acceptability for the mixed jam. The jam prepared at optimum conditions of coconut and pineapple pulp showed a good sensory acceptability after 6xa0months of storage at 28u2009±u20092 and 37xa0°C storage conditions on the basis of physicochemical and sensory attributes.

Jackfruit ( Artocarpus heterophyllus Lam.)

Abstract: This chapter deals with the important features of jackfruit composition, growth, maturation and harvest. Postharvest handling methodology concentrates on the normal packhouse unit operations with emphasis on packaging of bulbs as a unit package for retail marketing. The chapter further describes various value added products developed from jackfruit such as minimally processed, dehydrated, frozen and canned bulbs as well as ready-to-serve beverages, fruit bars and curry. The various by-products from seeds, unfertilized floral parts, and the outer perianth are also discussed. These products include starch from the seeds, leather-like products from unfertilized floral parts and pectin from the outer perianth portion. Finally, future requirements for improving the commercial utility of jackfruit are also highlighted.

A refreshing beverage from mature coconut water blended with lemon juice.

Coconut water obtained from the mature coconuts was blended with lemon juice to develop a refreshing beverage. The levels of total soluble solids (°Brix) in the coconut beverage and lemon juice (%), were optimized using response surface methodology and considering pH, CIE L* value and sensory attributes (colour, aroma, taste, consistency and overall acceptability) as responses. A number total of 14 experiments were carried out following Central Composite Rotatable Design (CCRD) keeping 6 experiments at centre point. The data obtained were analyzed using multiple regression technique and the quadratic equations (R2, 98.14–99.89xa0%) were found to fit well in describing the effect of variables on responses studied. An optimum condition for the coconut water beverage was obtained at 13.5°Brix blended with 2xa0% lemon juice. The mature coconut water beverage blended with lemon juice showed a shelf-life of 6xa0months in packed conditions at low (5xa0°C), ambient (25u2009±u20092xa0°C) and high (37xa0°C) temperatures on the basis of physicochemical, microbiological and sensory attributes.

Process optimization for osmo-dehydrated carambola (Averrhoa carambola L) slices and its storage studies.

An osmotic-dehydration process protocol for Carambola (Averrhoacarambola L.,), an exotic star shaped tropical fruit, was developed. The process was optimized using Response Surface Methodology (RSM) following Central Composite Rotatable Design (CCRD). The experimental variables selected for the optimization were soak solution concentration (°Brix), soaking temperature (°C) and soaking time (min) with 6 experiments at central point. The effect of process variables was studied on solid gain and water loss during osmotic dehydration process. The data obtained were analyzed employing multiple regression technique to generate suitable mathematical models. Quadratic models were found to fit well (R2, 95.58 - 98.64xa0%) in describing the effect of variables on the responses studied. The optimized levels of the process variables were achieved at 70°Brix, 48xa0°C and 144xa0min for soak solution concentration, soaking temperature and soaking time, respectively. The predicted and experimental results at optimized levels of variables showed high correlation. The osmo-dehydrated product prepared at optimized conditions showed a shelf-life of 10, 8 and 6xa0months at 5xa0°C, ambient (30u2009±u20092xa0°C) and 37xa0°C, respectively.