Saroj Giri | Indian Institute of Technology Kharagpur (original) (raw)

Papers by Saroj Giri

Shelf-life of Guava (Psidium guajava L.) under active packaging was studied based on produce, fil... more Shelf-life of Guava (Psidium guajava L.) under active packaging was studied based on produce, film and system parameters such as respiration rate of produce, film permeability and in-pack environmental conditions. Potassium permanganate embedded in silica crystals were used in the form of sachets as active ingredient for ethylene absorption inside packages. The designed modified atmosphere (MA) packages using LDPE film (76.2 μm thickness) were stored at 8 ± 2 °C. Most of the physico-chemical and textural properties of guava fruits during storage were affected by incorporation of ethylene absorbent in a dependent manner. The in-pack gaseous composition was significantly suppressed in MA packages with and without absorbent under refrigerated storage condition. The reduced changes in fruit firmness, total soluble content (TSS), titratable acidity (TA) and color showed the effectiveness of use of absorbent sachets in extending shelf life of guava fruit. A significant reduction in decay ...

Journal of Food Science, 2020

Pigeon pea is the most prominently used protein source for human consumption. This is one of the ... more Pigeon pea is the most prominently used protein source for human consumption. This is one of the leading pulse utilized in various applications in food processing. Soaking is one of the mandatory unit operation required to convert it from raw to a consumable form. Insights into its mass transfer dynamics enable the design and optimization of processing conditions with due consideration of retention of its quality and nutrition. In the present investigation, the mass transfer dynamics of simultaneous water gain and solid loss taking place during soaking was studied. The experimental samples were soaked at 35, 50, 75, 85, and 100°C to represent the lower and upper gelatinization temperatures. The water diffusivities varied from 5.492 × 10 −10 to 13.84 × 10 −10 m 2 /s when soaking temperature was increased from 35 to 100°C. Similarly, solid diffusivities vary between 6.27 × 10 −10 at 35°C and 9.48 × 10 −10 m 2 /s at 100°C. The activation energies of both the phenomenon were estimated using the Arrhenius equation. The mass transfer process has been identified with three distinct stages. The first stage was characterized by void filling, expansion, and solid hydration. The second stage was marked at 5% of solid loss and characterized by solid loss, while the third stage contributed to the starch gelatinization process. Simultaneous water gain and solid loss in the grain was observed throughout the process at varying rates. The insights into mass transfers from this study can help in further modeling of pigeon pea soaking behavior.

Journal of food science and technology, 2018

Probiotic soy-cheese spread was prepared by fermenting soymilk with specific probiotic starter cu... more Probiotic soy-cheese spread was prepared by fermenting soymilk with specific probiotic starter culture, and there after processing the coagulated mass. Soy cheese spread samples had more than 10 cfu/g of viable probiotic count at the time of preparation; and had around 17.6% protein, 25.3% fat and 19.8% total soluble sugar. Compared to commercially available dairy cheese spread, probiotic soy cheese spread had significantly higher protein and anti-oxidant activity. Soy cheese spreads, prepared from pure soymilk as well as by mixing with dairy milk, were studied with respect to the differences in their rheological behavior during storage at refrigerated conditions. A dynamic oscillatory test was used to measure the viscoelastic properties of spreads at 0, 7, 14, 21 and 28 days of storage. It was observed that the storage modulus (G') was higher than the loss modulus (G″) throughout the storage period indicating that the soy cheese spreads exhibit predominantly elastic behavior. T...

Fruits, when harvested have high moisture content and higher water activity that provides suitabl... more Fruits, when harvested have high moisture content and higher water activity that provides suitable ground for the growth of microorganisms. In addition, the biochemical and metabolic processes do not cease; though the fruit have left their parent plants. The processes such as respiration, senescence, and conversion of starch etc. contribute to the degradation process. Therefore, preservation of these fresh fruits becomes the top most priority for the producers, dealers and vendors. More than 100 methods are followed worldwide for preservation of different kinds and forms of foods. Most of these technologies aim at controlling the microbial growth for food safety, simultaneously altering the composition, colour, and taste of the produce. The likeness and public awareness for consumption of minimally processed or fresh like food has brought the concept of hurdle technology. The technology initially applied to meat preservation, has evolved into preservation of minimally processed foods, processed foods etc. This involves combination of two or more methods that act synergistically, like application of chlorine, ozone, chemical, ultrasound, hyperbaric pressure, active packaging/MAP, edible coating, electromagnetic waves in moderate doses and storage at suboptimal temperature and humidity, causing least damage to the quality parameters, thereby extending the shelf life of fresh fruits.

Pulses constitute an important part of the daily diet of vegetarian population as a major source ... more Pulses constitute an important part of the daily diet of vegetarian population as a major source of protein. It is estimated that insects cause the most damage to the pulse grains during storage and pulse bruchids are the major storage pests. The stored pulses are usually fumigated to wade away the insect infestation. The residual effect of these chemicals on public health and growing resistance of these insects to chemicals have encouraged use of chemical free disinfestations measures. Microwave radiation provides safe and hygienic mode of disinfestation. Dielectric heating of the biomaterials (grain and insects), depends largely on the moisture content in the product. Therefore, differential heating during microwave exposure seems to be a better option for food grain disinfestation. The most heat tolerant stage of pulse bruchids, adult (Callosobruchus maculatus), adults were subjected to microwave heating in a domestic microwave (2450 MHz, 900W) oven for different grain bed thickness (single layer to 2.0 cm). It was observed that as the grain bed depth increased the death time for the adults increased. Hundred per cent mortality was achieved for adults in green gram (mc=8%, wb) at 50, 60, 90, 110, and 120 s for single layer,0.5, 1, 1.5, and 2cm with corresponding microwave power densities of 13, 5, 3, 1.75 and 1.5 W/g, respectively. Quality of the green gram in terms of germination ability, cooking quality, loss of moisture, colour values, were evaluated. The germination percentage and cooking time varied from 58 to 100 % and 27 to 31 minutes, respectively. The textural hardness decreased with progress in cooking time. Total moisture loss and Hunter Lab scale colour change (E) values varied from 0.054 to 0.622 % and 1.23 to 56 Debabandya Mohapatra et al 0.34, respectively for different treated samples with respect to control sample.

Journal of Food Processing and Preservation, 2000

Effects of extrusion variables on extrudate characteristics of fish muscle-rice flour blend conta... more Effects of extrusion variables on extrudate characteristics of fish muscle-rice flour blend containing intermediate moisture (30–50%) were studied in an indigenously developed single screw cooking extruder. Data analysis of the statistically designed response surface experiments showed that expansion ratio and bulk density of extrudates were most influenced by the barrel temperature followed by fish content of the feed. In contrast fish and moisture contents of the feed significantly influenced hardness. A set of optimum process conditions was arrived at 160C barrel temperature, 12% fish content and 27% moisture content. Under these conditions experimental expansion ratio and bulk density matched well with the values predicted from the response model, but hardness deviated significantly. Experimental properties of the extrudates were not, however, affected by the fish variety.

Shelf-life of Guava (Psidium guajava L.) under active packaging was studied based on produce, fil... more Shelf-life of Guava (Psidium guajava L.) under active packaging was studied based on produce, film and system parameters such as respiration rate of produce, film permeability and in-pack environmental conditions. Potassium permanganate embedded in silica crystals were used in the form of sachets as active ingredient for ethylene absorption inside packages. The designed modified atmosphere (MA) packages using LDPE film (76.2 μm thickness) were stored at 8 ± 2 °C. Most of the physico-chemical and textural properties of guava fruits during storage were affected by incorporation of ethylene absorbent in a dependent manner. The in-pack gaseous composition was significantly suppressed in MA packages with and without absorbent under refrigerated storage condition. The reduced changes in fruit firmness, total soluble content (TSS), titratable acidity (TA) and color showed the effectiveness of use of absorbent sachets in extending shelf life of guava fruit. A significant reduction in decay ...

Journal of Food Science, 2020

Pigeon pea is the most prominently used protein source for human consumption. This is one of the ... more Pigeon pea is the most prominently used protein source for human consumption. This is one of the leading pulse utilized in various applications in food processing. Soaking is one of the mandatory unit operation required to convert it from raw to a consumable form. Insights into its mass transfer dynamics enable the design and optimization of processing conditions with due consideration of retention of its quality and nutrition. In the present investigation, the mass transfer dynamics of simultaneous water gain and solid loss taking place during soaking was studied. The experimental samples were soaked at 35, 50, 75, 85, and 100°C to represent the lower and upper gelatinization temperatures. The water diffusivities varied from 5.492 × 10 −10 to 13.84 × 10 −10 m 2 /s when soaking temperature was increased from 35 to 100°C. Similarly, solid diffusivities vary between 6.27 × 10 −10 at 35°C and 9.48 × 10 −10 m 2 /s at 100°C. The activation energies of both the phenomenon were estimated using the Arrhenius equation. The mass transfer process has been identified with three distinct stages. The first stage was characterized by void filling, expansion, and solid hydration. The second stage was marked at 5% of solid loss and characterized by solid loss, while the third stage contributed to the starch gelatinization process. Simultaneous water gain and solid loss in the grain was observed throughout the process at varying rates. The insights into mass transfers from this study can help in further modeling of pigeon pea soaking behavior.

Journal of food science and technology, 2018

Probiotic soy-cheese spread was prepared by fermenting soymilk with specific probiotic starter cu... more Probiotic soy-cheese spread was prepared by fermenting soymilk with specific probiotic starter culture, and there after processing the coagulated mass. Soy cheese spread samples had more than 10 cfu/g of viable probiotic count at the time of preparation; and had around 17.6% protein, 25.3% fat and 19.8% total soluble sugar. Compared to commercially available dairy cheese spread, probiotic soy cheese spread had significantly higher protein and anti-oxidant activity. Soy cheese spreads, prepared from pure soymilk as well as by mixing with dairy milk, were studied with respect to the differences in their rheological behavior during storage at refrigerated conditions. A dynamic oscillatory test was used to measure the viscoelastic properties of spreads at 0, 7, 14, 21 and 28 days of storage. It was observed that the storage modulus (G') was higher than the loss modulus (G″) throughout the storage period indicating that the soy cheese spreads exhibit predominantly elastic behavior. T...

Fruits, when harvested have high moisture content and higher water activity that provides suitabl... more Fruits, when harvested have high moisture content and higher water activity that provides suitable ground for the growth of microorganisms. In addition, the biochemical and metabolic processes do not cease; though the fruit have left their parent plants. The processes such as respiration, senescence, and conversion of starch etc. contribute to the degradation process. Therefore, preservation of these fresh fruits becomes the top most priority for the producers, dealers and vendors. More than 100 methods are followed worldwide for preservation of different kinds and forms of foods. Most of these technologies aim at controlling the microbial growth for food safety, simultaneously altering the composition, colour, and taste of the produce. The likeness and public awareness for consumption of minimally processed or fresh like food has brought the concept of hurdle technology. The technology initially applied to meat preservation, has evolved into preservation of minimally processed foods, processed foods etc. This involves combination of two or more methods that act synergistically, like application of chlorine, ozone, chemical, ultrasound, hyperbaric pressure, active packaging/MAP, edible coating, electromagnetic waves in moderate doses and storage at suboptimal temperature and humidity, causing least damage to the quality parameters, thereby extending the shelf life of fresh fruits.

Pulses constitute an important part of the daily diet of vegetarian population as a major source ... more Pulses constitute an important part of the daily diet of vegetarian population as a major source of protein. It is estimated that insects cause the most damage to the pulse grains during storage and pulse bruchids are the major storage pests. The stored pulses are usually fumigated to wade away the insect infestation. The residual effect of these chemicals on public health and growing resistance of these insects to chemicals have encouraged use of chemical free disinfestations measures. Microwave radiation provides safe and hygienic mode of disinfestation. Dielectric heating of the biomaterials (grain and insects), depends largely on the moisture content in the product. Therefore, differential heating during microwave exposure seems to be a better option for food grain disinfestation. The most heat tolerant stage of pulse bruchids, adult (Callosobruchus maculatus), adults were subjected to microwave heating in a domestic microwave (2450 MHz, 900W) oven for different grain bed thickness (single layer to 2.0 cm). It was observed that as the grain bed depth increased the death time for the adults increased. Hundred per cent mortality was achieved for adults in green gram (mc=8%, wb) at 50, 60, 90, 110, and 120 s for single layer,0.5, 1, 1.5, and 2cm with corresponding microwave power densities of 13, 5, 3, 1.75 and 1.5 W/g, respectively. Quality of the green gram in terms of germination ability, cooking quality, loss of moisture, colour values, were evaluated. The germination percentage and cooking time varied from 58 to 100 % and 27 to 31 minutes, respectively. The textural hardness decreased with progress in cooking time. Total moisture loss and Hunter Lab scale colour change (E) values varied from 0.054 to 0.622 % and 1.23 to 56 Debabandya Mohapatra et al 0.34, respectively for different treated samples with respect to control sample.

Journal of Food Processing and Preservation, 2000

Effects of extrusion variables on extrudate characteristics of fish muscle-rice flour blend conta... more Effects of extrusion variables on extrudate characteristics of fish muscle-rice flour blend containing intermediate moisture (30–50%) were studied in an indigenously developed single screw cooking extruder. Data analysis of the statistically designed response surface experiments showed that expansion ratio and bulk density of extrudates were most influenced by the barrel temperature followed by fish content of the feed. In contrast fish and moisture contents of the feed significantly influenced hardness. A set of optimum process conditions was arrived at 160C barrel temperature, 12% fish content and 27% moisture content. Under these conditions experimental expansion ratio and bulk density matched well with the values predicted from the response model, but hardness deviated significantly. Experimental properties of the extrudates were not, however, affected by the fish variety.