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The effect of microwave output power and sample amount on effective moisture diffusivity were investigated using microwave drying technique on round okra (Hibiscus esculentus L.). The various microwave output powers ranging from 180 to 900 W were used for the determination of effective moisture diffusivity for constant sample amount of 100 g okra. To examine the effect of sample amount on effective moisture diffusivity, the samples in the range of 25-100 g were dried at constant microwave output power of 360 W. By increasing the microwave output powers and decreasing the sample amounts, the effective moisture diffusivity values ranged from 20.52Â10 À10 to 86.17Â10 À10 and 34.87Â10 À10 to 11.91Â10 À9 m 2 /s À1 , respectively. The modeling studies were performed to illustrate the relationship between the ratio of the microwave output power to sample amount and effective moisture diffusivity. The relationship between drying constant and effective moisture diffusivity was also estimated.

We investigated the effects of process parameters (substrate concentration, enzyme concentration, temperature and pH) on the hydrolysis and solubilization of sesame cake protein as well as enzyme stability. The sesame cake protein was hydrolyzed by Alcalase enzyme (a bacterial protease produced by a selected strain of Bacillus Licheniformis) that was chosen among five commercial enzymes examined. The optimum process conditions for hydrolysis and solubilization were obtained as 15 g L −1 substrate concentration, 3 ml L −1 enzyme concentration, 50 o C and pH 8.5. Under these conditions, the values of degree of hydrolysis and solubilization were found as 26.3% and 82.1%, respectively, and enzyme lost its activity by approx. 56% at the end of 120 min processing time. Modeling studies were performed to determine the kinetics of hydrolysis, solubilization and enzyme inactivation. The relationship between hydrolysis and solubilization was found linear for all experimental conditions examined. The inactivation energy of Alcalase at the temperature range of 45-55 o C was determined to be 25544 J mol −1 .

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In this study, kefir grain biomass growth was investigated in whey enriched with some additives such as yoghurt, milk, glucose, sucrose, yeast extract and carob extract. The fermentation experiments were carried out at 27°C for 10 days by refreshing the cultivation media at the end of each 24 h fermentation period. Maximum and minimum biomass increases were obtained as 1,438 and 836% in whey enriched with 5% (w/v) yeast extract and 10% (v/v) carob extract, respectively. Kefir biomass increase and fermentation kinetics were examined at different temperatures (17, 27, 37°C) and different initial kefir grain concentrations (2.5, 5, 7.5%) for selected culture mediums (in whey and in whey enriched with milk and yoghurt). Optimum temperature and initial grain concentration for kefir biomass growth were obtained as 27°C and 5% for all examined mediums. Modelling studies were performed and various kinetic models tested to represent the kefir biomass growth and fermentation kinetics. The convenience of the kefir biomass growth to the Monod kinetics was also examined. Practical Applications The varied microbial composition of kefir grains provides novel applications to them, such as, in bread production as baker's yeast, cheese production, polysaccharide production, volatile aroma compound production and ethanol production. The biomass increase of kefir grains by traditional inoculation in milk is relatively low, hence to use kefir grains in commercial applications their production has to be improved using alternative cultivation mediums and optimizing the process conditions. So in the study presented by this article the kinetics of kefir grain biomass growth was investigated in whey (an alternative raw material for kefir biomass production that is a dairy liquid waste of negligible cost) enriched with additives such as yoghurt, milk, glucose, sucrose, yeast extract and carob extract to improve the biomass production of kefir and use the whey as an effective low cost substrate. Also the effect of temperature and initial kefir grain concentration on biomass production and fermentation were examined and different mathematical models were analyzed to represent the kefir biomass growth and kefir fermentation kinetics.

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In the present study, the hydrolysis of sesame cake protein was performed by Alcalase, a bacterial protease produced by Bacillus licheniformis, to investigate the reaction kinetics of sesame cake hydrolysis and to determine decay and product inhibition effects for Alcalase. The reactions were carried out for 10 min in 0.1 L of aqueous solutions containing 10, 15, 20, 25, and 30 g protein/L at various temperature and pH values. To determine decay and product inhibition effects for Alcalase, a series of inhibition experiments were conducted with the addition of various amounts of hydrolysate. The reaction kinetics was investigated by initial rate approach. The initial reaction rates were determined from the slopes of the linear models that fitted to the experimental data. The kinetic parameters, K(m) and V(max), were estimated as 41.17 g/L and 9.24 meqv/L x min. The Lineweaver-Burk plots showed that the type of inhibition for Alcalase determined as uncompetitive, and the inhibition constant, K(i), was estimated as 38.24% (hydrolysate/substrate mixture). Practical Application: Plant proteins are increasingly being used as an alternative to proteins from animal sources to perform functional roles in food formulation. Knowledge of the kinetics of the hydrolysis reaction is essential for the optimization of enzymatic protein hydrolysis and for increasing the utilization of plant proteins in food products. Therefore, in the present study, the hydrolysis of sesame cake protein was performed by Alcalase, a bacterial protease produced by B. licheniformis, to investigate the reaction kinetics of sesame cake hydrolysis and to determine decay and product inhibition effects for Alcalase.