T.K. Goswami

Piper nigrum and Piperine: An Update

Black pepper (Piper nigrum L.) is a very widely used spice, known for its pungent constituent piperine. However, in addition to its culinary uses, pepper has important medicinal and preservative properties, and, more recently, piperine has been shown to have fundamental effects on p‐glycoprotein and many enzyme systems, leading to biotransformative effects including chemoprevention, detoxification, and enhancement of the absorption and bioavailability of herbal and conventional drugs. Based on modern cell, animal, and human studies, piperine has been found to have immunomodulatory, anti‐oxidant, anti‐asthmatic, anti‐carcinogenic, anti‐inflammatory, anti‐ulcer, and anti‐amoebic properties. In this review, the chemical constituents, biological activities, effects of processing, and future potential of black pepper and piperine have been discussed thoroughly. Copyright

A Review on the Functional Properties, Nutritional Content, Medicinal Utilization and Potential Application of Fenugreek

Fenugreek (Trigonella foenum-gracum) is one of the most promising medicinal herbs, known from ancient times, having nutritional value too. Its green leaves and seeds are used for multipurpose. 100 g of seeds provide more than 65% of dietary fibre due to its high fibre content and it has an ability to change food texture. It is well known for its gum, fibre, alkaloid, flavonoids, saponin and volatile contents. In various medicinal applications, it works as antidiabetic, anticarcinogenic, remedy for hypocholesterolemia and hypoglycemia, antioxidant, antibacterial agent, gastric stimulant, and anti-anorexia agent. In modern food technology, it is used as food stabilizer, adhesive and emulsifying agent due its fibre, protein and gum content. Its protein is found to be more soluble (91.3%) at alkaline pH of 11. This review article presents the major medicinal and other beneficial uses of fenugreek discovered through last 30 years of research in animal and human subjects as well as in other experimental studies.

Design of a cryogenic grinding system for spices

Abstract The fat content of spices poses problems of temperature rise and sieve clogging during grinding. Due to this temperature rise, spices lose a significant fraction of their volatile oil or flavouring components. Therefore, a cryogenic grinding system was designed and developed to cool the spices before feeding to the grinder and also maintain the cryogenic temperature in the grinding zone. The main components of the cryogenic grinding system are a precooler and grinder. The precooler consists of a screw conveyor assembly, a compressor, a liquid nitrogen dewar and power transmission unit. The design considerations, calculations and development of the precooler have been discussed in the paper. A commercially available grinder was adopted for this purpose. The tests conducted on grinding of cumin seed revealed that it could be successfully ground below the temperature of −70°C. Above this temperature, sieve clogging took place. The increase in grinding temperature from−160°C to −70°C resulted in a significant increase in particle size of the product and specific energy consumption in grinding. A variation in volatile oil content was obtained in the range of 3.30–3.26 ml/100 g with increasing temperature from −160°C to −70°C, but this variation was found to be non-significant at 5% level.

Mathematical modeling of withering characteristics of tea leaves

The withering characteristics of tea leaves were examined for different temperatures. Tea leaves were withered at a temperature range of 20–45°C with a constant air velocity of 1.1 m/s. The experimental results illustrated the absence of constant-rate drying period and withering took place only in the falling-rate period. During the falling-rate period, at constant drying air flow rate, the drying rate increased and drying time decreased with the increase in drying air temperature. Drying models of Henderson and Pabis and Page were evaluated based on mean bias error (EMB), root mean square error (ERMS), correlation coefficient (R2), and the chi square (χ2). The Henderson and Pabis model was found to be a better model for describing the withering characteristics of tea leaves for each of the temperatures of 20, 25, 30, and 35°C. The values obtained from Page model were found to be more reasonable for temperatures of 40 and 45°C than the other model. Both the models closely fitted the withering data within a certain range of temperature. The Henderson and Pabis model gave better prediction and satisfactorily described the withering characteristics of tea leaves at temperatures lower than 40°C whereas the Page model fitted well at temperatures greater than 40°C.

Role of feed rate and temperature in attrition grinding of cumin

Abstract Experiments on grinding of cumin seed were conducted in a double disc, single rotating, attrition mill to find the effect of feed rate and temperature of cumin on some dependent variables such as rise of temperature and size of the ground cumin, specific energy consumption and Bond’s work index. The temperature was lowered with the help of liquid nitrogen. There was a gradual increase in temperature rise, and decrease in size of the ground cumin, but the specific energy consumption and work index were decreased first and then increased with increase in feed rate of cumin in the attrition mill. The effect of feed temperature of cumin at −100 °C gave quite low values of rise in temperature, specific energy consumption, work index and high value of reduction ratio compared to feed temperatures of cumin at 30 and −40 °C. The difference in said dependent variables were not of much significance between feed temperatures of cumin ground at 30 and −40 °C.

Mechanical properties of cumin seed (Cuminum cyminum linn.) under compressive loading

Abstract The moisture dependent mechanical properties of cumin seed were measured in terms of average compressive force, seed rupture force, deformation and energy absorbed. The cumin seeds in the moisture content range of 7 to 22% d.b. were quasi-statically loaded in the horizontal and vertical orientations. The force increased with increasing deformation and decreasing moisture content in the horizontal and vertical orientations. Force required to initiate seed rupture decreased from 50 to 40 N and 31 to 20.3 N and seed deformation increased from 0.307 to 0.327 and 0.285 to 0.428 with increase in moisture content from 7 to 13% d.b. and 7 to 12% d.b. for the horizontal and vertical orientations respectively. The energy absorbed increased with increasing moisture content in the horizontal and vertical orientations and it followed a second-order polynomial regression. Cumin seed loaded in the vertical orientation required more energy for rupture than that in the horizontal orientation. Maximum energy absorbed was found to be 14.8 and 20.4 mJ at the moisture content of 7% d.b. in the horizontal and vertical orientations respectively.

Measurement and Modeling of Respiration Rate of Guava (CV. Baruipur) for Modified Atmosphere Packaging

Several experiments were conducted at different storage temperatures for generating respiration data using close system method for respiration. A respiration rate model, based on enzyme kinetics and the Arrhenius equation was proposed for predicting the respiration rates of Guava as a function of O2 and CO2 concentrations and storage temperature. Temperature was found to influence the model parameters. In this model, the dependence of respiration rate on O2 and CO2 was found to follow the uncompetitive inhibition. The enzyme kinetic model parameters, calculated from the respiration rate at different O2 and CO2 concentration were used to fit the Arrhenius equation against different storage temperature. The activation energy and respiration pre-exponential factor were used to predict the model parameters of enzyme kinetics at any storage temperature between 0–30°C. The developed models were tested for its validity at 12°C and it was found to be in good agreement (the mean relative deviation moduli between the predicted and experimental respiration rates were found to be 8.95% and 8.02% for O2 consumption and CO2 evolution, respectively) with the experimentally estimated respiration rates.

Development and validation of a comprehensive model for map of fruits based on enzyme kinetics theory and arrhenius relation

MAP is a dynamic system where respiration of the packaged product and gas permeation through the packaging film takes place simultaneously. The desired level of O2 and CO2 in a package is achieved by matching film permeation rates for O2 and CO2 with respiration rate of the packaged product. A mathematical model for MAP of fresh fruits applying enzyme kinetics based respiration equation coupled with the Arrhenious type model was developed. The model was solved numerically using MATLAB programme. The model was used to determine the time to reach to the equilibrium concentration inside the MA package and the level of O2 and CO2 concentration at equilibrium state. The developed model for prediction of equilibrium O2 and CO2 concentration was validated using experimental data for MA packaging of apple, guava and litchi.

DRYING KINECTICS OF PADDY USING THERMOGRAVIMETRIC ANALYSIS

The thermogravimetry (TG) and derivative thermogravimetry (DTG) were used to study the drying kinetics of the paddy. TG experiments were carried out at different heating rates (1, 3, 10 K/min) to study the drying kinetics. The Activation energy and pre exponential factors from the Arrhenious equation were calculated for the drying curves using ASTM and OZAWA-FLYNN WALL analysis. The results showed that the drying reaction was the second order reaction and the activation energy values changing with the partial mass loss representing that the drying reaction was of complex type of reaction. The isothermal drying curves predicted from the dynamic curves showed reasonably high mass loss occurred at moderate range of temperatures of 60–100°C.

Role of cryogenics in food processing and preservation.

Food materials are perishable by nature. They require processing or preservation techniques to enhance the storage life. Cryogenics is a branch of engineering wherein production of cryogen and the maintenance of low temperature technologies are studied. One such cryogen, liquid nitrogen (LN2) has a tremendous potential to be used as a total loss refrigerant. In this paper, the different aspects of the utilization of LN2 as a refrigerant and as a gas are discussed in details.In freezing for individual quick freezing LN2 can be used as a refrigerant to get an ultra rapid freezing. Due to its rapidity LN2 freezing is capable of producing small ice crystals in size and there by helps immensely in retaining quality reducing substantial amount of drip loss.LN2 has gained tremendous popularity for the transportation of frozen foods. Apart from the intermittent spraying of LN2, dump charging method has been also developed wherein the refrigerant required for a point to point transportation is supplied to a frozen cargo before the commencement of the journey eliminating the requirement of LN2 vessel to be taken on board.Grinding is a technique which reduces the size of spices, considerably increasing the surface area available to impart flavor to any prepared food. Unfortunately, a substantial amount of flavoring compounds is lost due to the increase in temperature while using conventional grinding methods. LN2 can act as a rescuer for retention of quality by reducing the spice as well as grinder temperature substantially. Experimental analysis reveals that the loss of volatile component and particle size distribution of the ground spices are more than the satisfaction level of the processor.LN2 has the capacity to both lower the temperature and flush off the inside air of a closed container. This serves a dual purpose: The temperature of the closed chamber is brought to the desired level almost instantaneously and the gas compost ion can be changed immediately. The application of LN2 helps to minimize the need for high-capacity refrigeration system. Only 10% of the installation capacity is required for maintaining the desired temperature.