Browsing by Author "Alok Jha"

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Antioxidant and antibacterial potential of pomegranate peel extracts
(Springer, 2014) Shalini Malviya; Arvind; Alok Jha; Navam Hettiarachchy
Pomegranate peels of Ganesh variety were subjected to extraction using different solvents viz. water, methanol and ethanol either alone or in combination with water. The extraction yield, antioxidant activity (DPPH and ABTS inhibition) and total phenolic contents were evaluated. Highest yield was obtained from 50 % ethanol: 50 % water (16.3 ± 1.99 %). The DPPH and ABTS inhibition activity was found to be the highest for methanol and 70 % ethanol: 30 % water extract (79.5 ± 6.5; 94.6 ± 6.10), respectively. The phenolic content was the highest in the aqueous extract (438.3 ± 14.15). The antibacterial activity of peel extracts was tested against four bacterial strains, Staphylococcus aureus, Enterobacter aerogenes, Salmonella typhi and Klebsiella pneumoniae and the extracts demonstrated remarkable antibacterial activities against all the tested bacterial strains. The 70 % ethanol: 30 % water and 100 % water extract had a higher antioxidant activity and phenolic content and has the potential for nutraceutical application. © 2013, Association of Food Scientists & Technologists (India).
Appropriate solvents for extracting total phenolics, flavonoids and ascorbic acid from different kinds of millets
(Springer, 2015) Rohit Upadhyay; Alok Jha; Satyendra P. Singh; Arvind Kumar; Mithilesh Singh
Different polar solvents (methanol, acetone and water) were tested for their extractability of phenolic compounds from millets grown in India namely, sawan (Echinochloa frumentacea), kodo (Paspalum scrobiculatum), jowar (Sorghum bicolor) and bajra (Pannisetum typhoides). The extracts were evaluated for their total phenolics, flavonoids, ascorbic acid content and antioxidant activity. The acetone extracts reported highest total phenolics content (TPC) between 0.8 and 2.64 mg gallic acid equivalents/g flour dry matter; the lowest for sawan and the highest for bajra. Ascorbic acid content did not differ significantly between different millets (p < 0.05) except for sawan (lowest). The antioxidant assays included 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl radical (OH*) scavenging and reducing power. The activity in millets followed as bajra > jowar > kodo > sawan. The polyphenols in extracts were also analyzed by high-performance liquid chromatography (HPLC) at 290 nm. A clear correlation obtained between the TPC, flavonoids content and antioxidant activity. Acetone showed better extractability and thus can be appropriate solvent to extract phenolic compounds in millets used in this study. © 2013, Association of Food Scientists & Technologists (India).
Chemical kinetic modeling of nutricereal based fermented baby food for shelf life prediction
(Bentham Science Publishers, 2019) Prasad Rasane; Alok Jha; Sawinder Kaur; Vikas Kumar; Nitya Sharma
Background: A nutricereal based fermented baby food was investigated to predict its shelf life using chemical kinetic modeling. An optimized baby food formulation, packaged in metalized polyester packets was stored at accelerated conditions for 180 days and analyzed for hydroxy methyl furfural (HMF), thiobarbituric value (TBA), free fatty acid content (FFA) and sensory characteristics. Result: Shelf life model based on chemical and sensory acceptability was derived using Arrhenius equation modeling. Thus, the baby food had a predictive shelf life of 54 weeks when stored at 10°C in metalized polyester based on the chemical (HMF, TBA and FFA) and sensory (overall acceptability) characteristics. A most suitable model based on FFA was developed considering lowest root mean square (RMS) percentages and least deviations in actual and predicted values. Conclusion: Chemcial kinetics could be applied to determine the shelf life of the fermented baby foods. HMF, TBA and FFA play key role in the shelf life of the stored fermented product. A model based on FFA is most suitable to determine the shelf life of the powdered nutricereal based fermented baby food packged in metalized polyster, stored at 10°C. © 2019 Bentham Science Publishers.
Detection of adulteration in milk: A review
(Blackwell Publishing Ltd, 2017) Amrita Poonia; Alok Jha; Rajan Sharma; Harikesh Bahadur Singh; Ashwini Kumar Rai; Nitya Sharma
Milk is a wholesome nutritious dairy product and is consumed by a majority of the population worldwide for drinking as such, as well as via dairy products. However, the practice of adulteration of milk invariably reduces its quality and may introduce hazardous substances into the dairy supply chain jeopardising consumers’ health. Various instances of adulteration of milk have been reported globally, wherein substances such as extraneous water, foreign proteins, whey proteins, melamine and urea, vegetable or animal fats, plus many minor constituents of milk fat have been added as potential adulterants in milk and milk products. This review focusses on the different methods of detection of these adulterants in milk using techniques such as DSC, RP-HPLC, LC-GC, HPTLC, immunoassays: CE, ELISA, FAMPST, FTIR, NIR spectroscopy, PAGE, IEF, DNA-based methods and MALDI-MS that have been developed and employed for the last 25 years. The combination of advanced IR spectroscopy and chemometrics provides a powerful tool for quality and authenticity analysis of milk. An electronic tongue is an easy and economic tool for the detection of caprine milk adulterations with bovine milk. Biosensors having the ability to furnish real-time signals have been developed for the detection of urea in milk. An attempt has been made to give a clear understanding of the most suitable methods for the determination of various sources of adulteration. © 2016 Society of Dairy Technology
Development of a process for manufacture of long-life dairy dessert kheer and its physicochemical properties
(2011) Alok Jha; Ashok A. Patel; Teralandur K.S. Gopal; Ravishankar C. Nagarajarao
Kheer, a traditional milk product of South-east Asia, containing cooked rice grains in a creamy sweetened concentrated milk, has no large-scale production owing to its poor shelf-life. Shelf-life was improved by developing a process based on in-pouch thermal processing employing a rotary retort. Product development included optimisation of rice/milk solids ratio (0.18-0.52) and total milk solids levels (16-26%) to simulate the conventional product in taste, appearance and textural attributes. Various process lethality values (F o=12.4-14.8) were examined with regard to product quality. While the thiobarbituric acid value tended to increase (0.073-0.081), the reflectance value (35.3-43.4) declined with increasing F o. The pH of the product (6.04-6.10) showed a slight tendency to increase with F o. Sensorily, the product was found to be acceptable for a period of 150days at 37°C. © 2011 Society of Dairy Technology.
Development of a process for manufacture of the shelf-stable chhana roll and its physicochemical properties
(Blackwell Publishing Ltd, 2014) Balraj Singh Jat; Alok Jha; Mahwash Jafri; Dinesh Chandra Rai; Anuj Kumar Gautam
The chhana roll is an indigenous, milk-based sweet of the Indian subcontinent that is sold at cottage scale without any packaging. It is prepared from chhana, an intermediate product obtained from heat and acid coagulation of milk. In order to enhance its shelf life, the product was processed in a retort pouch using a stationary retort. Product optimization was carried out through response surface methodology using two variables, i.e., level of nisin (0.00-692IU/g) and process time (15-25min). The Fo varied from 4.48 to 12.04min. The lag period for the heating curve, jh (0.82-0.96), heating rate index, fh (8.5-13.9min) and the lag factor for the cooling curve, jc (0.83-1.77) implied a conductive heating regime. The total process time (B') ranged from 13.94 to 28.13min. The process time of 15min and nisin concentration of 118.73IU/g resulted in a shelf life of 90 days at 37C. © 2013 Wiley Periodicals, Inc.
Development of a process for shelf stable dairy dessert dalia and its physico-chemical properties
(Academic Press, 2012) Alok Jha; Murli; Ashok Ambalal Patel; Teralandur Krishnaswamy Srinivasa Gopal; Chandragiri Nagarajarao Ravishankar
Dalia, is a traditional dairy food of Indian sub-continent. It is consumed as dessert by cooking cracked wheat (dalia grains) in milk along with addition of sugar. It is used as a breakfast food especially for growing children and also for old age people. It has a poor shelf life of 1-2 days. In order to enhance its shelf life, dalia was processed in tin-free steel cans at 121.1 °C in a rotary over pressure retort. Process lethality (Fo) was found to vary from 3.90 to 8.22 min for different formulations. The average composition of retort sterilized dalia dessert comprised of 29.60 g/100 g total solids (TS), 3.56 g/100 g protein, 0.84 g/100 g ash and 21.54 g/100 g total carbohydrates including 2.88 g/100 g amylose. The product had a short lag period for the heating curve, jh (0.40-0.85), small heating rate index, fh (3.2-5.5 min) and a short lag factor for the cooling curve, jc (0.91-1.10) implying essentially convective heating regime. The process time (B) was 10.20-15.78 min for Fo value of 3.90-8.22 min, whereas the cook value (Cg) was 28.95-54.03 min. Fo value of 4.15 min and nisin 376 IU/g yielded a product that was both safe and wholesome for 72 days at 37 °C. © 2012 Elsevier Ltd.
Development of a process for the manufacture of shelf stable dhal and its physico-chemical properties
(Springer India, 2015) Mahwash Jafri; Alok Jha; Prasad Rasane; Nitya Sharma
Thermally processed, ready-to consume dhal with natural sensory attributes was developed. Product optimization was done using two variables, retort process time and ratio of water to dhal. Dhal were packed in retortable pouches and processed in a stationary air–steam retort. The product was characterized by a short lag period for the heating curve, jh (0.52–0.64), small heating rate index, fh (3.9–6.5 min) and a short lag factor for the cooling curve, jc (0.53–0.73) implying essentially convective heating regime. The total process time (B’) was 11.56–40.25 min for Fo value of 2.30–27.30 min. Process time of 25 min at 121 °C and ratio of water to dhal of 2.5 yielded a product that was microbiologically safe as well as sensorily acceptable. During storage, chemical parameters like thiobarbituric acid and free fatty acid increased, while pH decreased with concomitant decrease in sensory scores. Textural properties like, consistency, cohesiveness and index of viscosity underwent a significant (P < 0.05) increase during the storage. © 2014, Association of Food Scientists & Technologists (India).
Effect of inulin on textural and sensory characteristics of sorghum based high fibre biscuits using response surface methodology
(Springer, 2014) Chandralekha Banerjee; Rakhi Singh; Alok Jha; Jayeeta Mitra
Five blends of sorghum (Sorghum bicolor) flour (25.0–45.0 %) and whole wheat flour were used to make biscuits using inulin (5.0–10.0 %) and guar gum (1.0–2.0 %). An experimental investigation was carried out with the aim of evaluating the effect of fat replacer (inulin) and sorghum flour on the quality of high fibre and low calorie biscuits. For this purpose, the biscuit dough and the biscuit samples were analyzed. The analysis was based on hardness of the dough, hardness of the biscuit, fracturability and overall acceptability (OAA) scores. Results showed that increasing the amount of sorghum flour in biscuit increased the dough hardness and biscuit hardness, whereas, biscuit fracturability decreased and OAA scores increased up to the level at which sorghum flour ranged from 35.0 to 40.0 % after which it decreased. An increase in the amount of inulin was followed by an increase in biscuit hardness, while, fracturability and OAA scores decreased and there was little effect on the dough hardness. Optimum conditions generated from the analysis was 40.8 % sorghum flour, 6.5 % inulin and 1.0 % guar gum. The predicted response in terms of dough hardness, fracturability, biscuit hardness and OAA were 212.4 g, 36.4 mm, 4.8 kg and 7.06, respectively. The desirability of the optimum condition was 0.827. © 2012, Association of Food Scientists & Technologists (India).
Effect of modified atmosphere packaging on the shelf life of lal peda
(Springer, 2015) Alok Jha; Arvind Kumar; Parul Jain; Anuj Kumar Gautam; Prasad Rasane
Lal peda is a traditional dairy-based sweet, popular in the Indian subcontinent, but it has a poor shelf life. The lal peda samples were packed in polyethylene bags filled with 3 different gaseous compositions (Air, 70 % N2: 30 % CO2 and 98 % N2) and stored at 10 °C. The shelf life was evaluated on the basis of changes in the microbial status of the product such as total plate count, yeast and molds and coliform counts and also the physico-chemical changes such as hydroxy methyl furfural (HMF), thiobarbituric acid (TBA) and free fatty acid (FFA). The microbial spoilage and the indices of chemical changes increased in all the samples with the progression of storage period. The samples packed with air showed significantly higher chemical deterioration and microbial spoilage as compared to the other two combinations. The results showed that samples packed with 70 % N2: 30 % CO2 combination had better shelf stability as compared to the samples packed under air and 98 % N2. © 2013, Association of Food Scientists & Technologists (India).
Effect of modified atmospheric packaging on chemical and microbial changes in dietetic rabri during storage
(Springer, 2015) Gajanan Ghayal; Alok Jha; Arvind Kumar; Anuj Kumar Gautam; Prasad Rasane
Rabri is a dairy based sweet popular in the Indian subcontinent. The high sugar and fat content impose restrictions on its consumption due to health reasons. Dietetic rabri was prepared by the replacement of sugar with aspartame. Inulin was added to partially replace the milk fat and to improve the consistency of rabri. The rabri samples were packed in the polyethylene bags filled with different gaseous compositions (Air, 50 % CO2:50 % N2 and 100 % N2) and stored at 10 °C. The shelf life was evaluated on the basis of changes in the chemical quality parameters such as HMF, TBA and FFA and microbial content such as total plate count, yeast and molds and coliform counts. The chemical parameters and microbial spoilage increased in all the samples with the progression of storage period. The samples packed with air showed significantly higher chemical deterioration and microbial spoilage as compared to the other two combinations. The samples packed with 100 % N2 were more shelf stable than with air and 50 % CO2:50 % N2 combinations. © 2013, Association of Food Scientists & Technologists (India).
Effect of modified atmospheric packaging on the shelf life of Kalakand and its influence on microbial, textural, sensory and physico-chemical properties
(Springer, 2015) Vishal Jain; Prasad Rasane; Alok Jha; Nitya Sharma; Anuj Gautam
Kalakand, a popular traditional milk sweet of Indian sub-continent, was packaged under air and modified atmospheric packaging (MAP) conditions (98 % N2, 98 % CO2 and 50%N2: 50%CO2). The samples were stored at 10, 25 and 37 °C and evaluated for various physico-chemical, microbial, textural and sensory changes, in order to establish the applicability of MAP for storage of Kalakand. It could be established that the MAP conditions of 50 % N2: 50 % CO2and storage at 10 °C, were the most suitable conditions for preserving the Kalakand for upto 60 days. © Association of Food Scientists & Technologists (India) 2014.
Enhancement of the functionality of bread by incorporation of Shatavari (Asparagus racemosus)
(Springer, 2014) Nishu Singh; Alok Jha; Anand Chaudhary; Ashutosh Upadhyay
In view of the wider consumption of bakery products, they could be good choice for the delivery of functionality. The present study attempts to develop a functional formulation of bread by incorporation of shatavari (Asparagus racemosus Willd.), which is an important medicinal plant of India. Central composite rotatable design (CCRD) was used for experiments in which yeast and shatavari powder were taken as variables. Response surface methodology (RSM) was used to optimize the bread formulations on the basis of hardness, adhesiveness, springiness, chewiness and cohesiveness as responses. Qualitative tests were performed for assessing the presence of phytochemicals in shatavari bread. Sensory attributes of the shatavari bread were evaluated using descriptive analysis technique. The optimum acceptable level for shatavari and yeast in bread was found to be 3.5 % and 4.96 %, respectively. All the phytochemicals such as alkaloid, steroid, terpenoid and saponin present in original herbs were also present in bread. However flavonoids were not found in the bread when analysed qualitatively and using TLC. © 2012, Association of Food Scientists & Technologists (India).
Heat penetration characteristics and physico-chemical properties of in-pouch processed dairy dessert (kheer)
(Springer, 2014) Alok Jha; A.A. Patel; T. K. Srinivasa Gopal; C.N. Ravishankar
Kheer, a traditional milk product of South East Asia, containing cooked rice grains in a creamy sweetened concentrated milk, has no large-scale production due to its poor shelf life. Shelf-life was improved by development of a process based on in-pouch thermal processing employing a rotary retort. Product development included optimization of rice-to-milk solids ratio (0.18–0.52) and total milk solids levels (16–26 %) to simulate the conventional product in taste, appearance and textural attributes. Various Fo values (12.4–14.8) were examined with regard to product quality. While the TBA value tended to increase (0.073–0.081) the reflectance value (35.3–43.4) declined with increasing Fo. The pH of the product (6.04–6.10) showed a slight tendency to increase with Fo. Sensorily, the product was found to be acceptable for a period of 150 days at 37 °C. © 2012, Association of Food Scientists & Technologists (India).
Improved functional properties of glycosylated soy protein isolate using D-glucose and xanthan gum
(Springer India, 2015) Ruiqi Li; Navam Hettiarachchy; Srinivas Rayaprolu; Mike Davis; Satchithanandam Eswaranandam; Alok Jha; Pengyin Chen
Functional properties of the soy protein need to improve to have better applications in food industry. Alkali extracted and acid precipitated soy protein isolate (SPI) was glycosylated using D-glucose (G) and Xanthan gum (X) via Maillard reaction to improve solubility. The effects of SPI to G and SPI to X ratios (SPI:G = 2:1, 1:1, and 1:2; SPI:X = 100:1 and 10:1) and incubation time (0, 6, 12, and 24 h) on the solubility and functional properties of glycosylated SPI were evaluated. The SPI:G ratio of 1:2 yielded a maximum degree of glycosylation of 71.1 %. The solubility of SPI after glycosylation significantly increased (P < 0.05) at pH 4.0–8.0 compared to SPI alone. Although the emulsion stability of glycosylated SPIs has not significantly increased (P > 0.05), the emulsifying activity improved significantly (P < 0.05). Glycosylation with SPI-X at a ratio of 10: 1 showed maximum emulsifying activity of 191.6 m2/g (SPI alone: 66.3 m2/g). Moreover, the SPI:X (ratio of 100:1) showed the maximum foaming activity (205 mL) compared to SPI alone (155 mL). The foaming stability of SPI (2.6 %) increased to 5.5 and 8.2 % when using xanthan gum at the ratio of 100:1 and 10:1, respectively. Glycosylated SPI with enhanced emulsifying and foaming properties has potential to improve the functional quality of the food products. © 2015, Association of Food Scientists & Technologists (India).
Influence of the solvents on the extraction of major phenolic compounds (Punicalagin, ellagic acid and gallic acid) and their antioxidant activities in pomegranate aril
(Springer, 2014) Mithilesh Singh; Alok Jha; Arvind Kumar; Navam Hettiarachchy; Ashiwini K. Rai; Divya Sharma
Phenolic compounds of fruits have been shown to maintain human health. However, the relative amounts of phenolic compounds and the variation in the types of phenolics are still poorly understood. The purpose of this study was to investigate the most effective solvent for extracting the potent antioxidant compounds, especially phenolics from pomegranate aril. Pomegranate aril was subjected to extraction using different solvents viz., water, ethanol, acetone and diethyl ether either alone or in combination, and the extraction yield, total phenolic contents, and antioxidant activity were investigated. The extracts derived from various solvents were also analysed using high performance liquid chromatography (HPLC) for quantification of major polyphenols (punicalagins, ellagic acid and gallic acid) of pomegranate. Amongst the tested solvents, combination of ethanol, diethyl ether and water (8:1:1) extract exhibited the highest 2, 2- diphenyl-1-picrylhydrazyl (DPPH) radical scavenging power (IC50 = 10.12 μg mL-1). Further, HPLC analysis of different extracts revealed that ethanol, diethyl ether and water (8:1:1) mixture contained significantly higher (p<0.05) amounts of punicalagin A (1.06 μg mg-1 extract), punicalagin B (2.07± 0.03 μg mg-1 extract), ellagic acid (34.5 μg mg-1 extract) and gallic acid (3.37 μg mg-1 extract) in comparison to the other solvents used for extraction. The results demonstrate that pomegranate aril is a good source of phenolic compounds with high antioxidant activity and the antioxidant activity is dependent on the type of solvent system that extracts different phenolic compounds with varying polarity. The solvent extracts that showed effective antioxidants activities have the potential for application in suitable food products. © Association of Food Scientists & Technologists (India) 2014.
Kinetics of changes in shelf life parameters during storage of pearl millet based kheer mix and development of a shelf life prediction model
(Springer, 2014) Durga Shankar Bunkar; Alok Jha; Ankur Mahajan; V.S. Unnikrishnan
Pearl millet, dairy whitener and sugar powder were blended for preparing pearl millet kheer mix. Pearl millet based kheer mix samples were stored at 8, 25, 37 and 45 °C under nitrogen flushing environment. Changes in HMF and TBA formation in the dry mix and sensory changes in reconstituted kheer were studied upto 180 days. In fresh dry mix, the average value of HMF recorded was 4.87 μmol/g which increased to 11.23, 13.67, 18.13, and 21.43 μmol/g at 8, 25, 37 and 45 °C, respectively after 180 days of storage. From an initial value of 0.067, the TBA value increased to 0.219, 0.311, 0.432 and 0.613 at 532 nm at 8, 25, 37 and 45 °C, respectively after 180 days of storage. Data generated from the chemical kinetics of HMF and TBA development that progressed during storage of pearl millet kheer mix were modeled using Arrhenius equations to predict the shelf life of the product. Changes in HMF and TBA followed first order reaction kinetics. It was found that the potential shelf life of the pearl millet based kheer mix was 396 days at 8 and 288 days at 25 °C, respectively. © 2012, Association of Food Scientists & Technologists (India).
Kinetics of HMF formation during storage of instant kheer mix powder and development of a shelf-life prediction model
(Blackwell Publishing Ltd, 2014) Alok Jha; Ashok Ambalal Patel
Kheer is one of the most widely consumed traditional dairy products of Southeast Asian nations including India. Because of its poor shelf life, which hinders its commercialization and large-scale industrial production, product is confined to domestic kitchens and small-scale manufacturers. A shelf-stable dry mix was produced by using spray-drying technology with an aim to develop a convenient formulation for the traditional kheer. Instant kheer mix (IKM) powder could be easily reconstituted into kheer. The shelf life of IKM powder stored at 30, 37 and 45C was determined. Various physicochemical changes in kheer mix powder were monitored during storage and their effects on sensory properties of reconstituted kheer were studied and correlated. The change in color of IKM powder was found to be a zero-order reaction. The activation energy (Ea), Arrhenius constant and Q10 value for the reaction were 106.50kJ/mol, 9.846×1,017M/wk and 3.8, respectively. The total and free hydroxymethylfurfural (HMF) formation during storage was found to increase and sensory scores found to decrease during storage. In fresh kheer mix powder, the average value recorded was 5.0μmol/L, which increased to 21.74μmol/L after 24 weeks of storage at 30C. At 37 and 45C, the total HMF content increased to 30.4 and 56.3μmol/L after respective storage durations of 16 and 8 weeks. These changes could be described well with first-order reaction kinetics. The rates of these reactions were highly temperature-dependent, the rates being higher at high temperature. The Ea and other activation parameters such as enthalpy, entropy and free energy of activation for these reactions were determined. The interrelationships between sensory and HMF changes were established. The sensory color was negatively correlated with absorbance and also with increase in HMF values. The shelf-life prediction model, which was developed based on the kinetic constants and the relationship between sensory and chemical parameters, could be useful in predicting the shelf life of kheer mix powder. Potential shelf life of kheer mix powder was found to be 92 weeks at 37C, which is comparable with most spray-dried powders. PRACTICAL APPLICATIONS: About 50% of the milk produced in India (117.0 million tons) is converted into traditional dairy foods. Traditional dairy foods include cereal-based dairy desserts, which are confined to domestic kitchens because of lack of technological processes for their large-scale manufacture. Packaging of these products is almost nonexistent. Market for such products is estimated to be about INR 50,000 crore (US$ 10.29 billion). Most of these products are consumed locally as they suffer from poor shelf life. Recent focus is on developing new and innovative processes for converting these traditional dairy foods into convenient formulations so that shelf life is enhanced and there is an ease of consumption. Development of a spray-dried process for large-scale manufacture of instant kheer mix with a potential shelf life of more than 92 weeks at ambient temperature could result in product diversification, export promotion and value addition for the food and dairy industry. © 2012 Wiley Periodicals, Inc.
Moisture sorption characteristics of lal peda at different storage temperatures
(2012) Arvind Kumar; Alok Jha; Parul Jain; Jatindra K. Sahu; Shalini Arora
Moisture sorption isotherms of lal peda, a heat-desiccated traditional milk product of Indian sub-continent were determined at 10, 25 and 37. °C over a water activity range of 0.113 to 0.868 using standard saturated salt solutions. The isotherms obtained were of sigmoid shape (type II) at all temperatures. Among five sorption models fitted, Guggenheim-Anderson-de Boer (GAB) model was fitted best to the sorption at three temperatures. The monolayer moisture content as calculated by the best fitted GAB model for desorption and adsorption processes at 10, 25 and 37. °C were 3.852, 4.551 and 5.235 and 3.214, 4.103 and 5.253% on a dry basis, respectively. The values of isosteric heat of sorption as calculated from Clausius-Clapeyron equation was found to increase with decreasing moisture content at lower moisture content. © 2012 Elsevier Ltd.
Moisture sorption isotherms of dietetic Rabri at different storage temperatures
(2013) Gajanan Ghayal; Alok Jha; Jatindra K Sahu; Arvind Kumar; Anuj Gautam; Ravindra Kumar; Prasad Rasane
Moisture sorption isotherms of dietetic Rabri were determined at 10, 25 and 37 °C over a water activity range of 0.113-0.868. Sorption isotherms at 37 °C were sigmoidal (type II) curves, while at 10 °C, they were of type V and Type I at 25 °C for both adsorption and desorption processes. Five sorption models were tested to fit the experimental data. Halsey's model for 10 °C, Caurie's model for 25 °C and Modified Mizrahi's model for 37 °C were found to be the best fit. There was a clear hysteresis effect at 10 °C, whereas the effect gradually decreased and diminished at 37 °C. © 2013 Society of Dairy Technology.