B.C. Sarkar

Mathematical modelling of thin layer hot air drying of carrot pomace

Thin layer carrot pomace drying characteristics were evaluated in a laboratory scale hot air forced convective dryer. The drying experiments were carried out at 60, 65, 70 & 75 °C and at an air velocity of 0.7 m/s. Mathematical models were tested to fit drying data of carrot pomace. The whole drying process of carrot pomace took place in a falling rate period except a very short accelerating period at the beginning. The average values of effective diffusivity ranged from 2.74 × 10−9 to 4.64 × 10−9 m2/s for drying carrot pomace. The activation energy value was 23.05 kJ/mol for the whole falling rate period.

Development and characterization of extruded product using carrot pomace and rice flour.

Dehydrated carrot pomace was added in different proportions (10-30%) to rice flour. The formulation was extruded at different moisture content (17-21%), screw speed (270-310 rpm) and die temperature (110-130°C). The experimental combinations were decided based on central composite rotatable design for four variables at five levels of each variable. The lateral expansion, bulk density, water absorption index, water solubility index, hardness and sensory characteristics were measured as responses. Significant regression models were established with the coefficient of determination, R² greater than 0.70. The results indicated that pomace proportion, screw speed and temperature significantly influenced (P<0.10) lateral expansion; moisture content and screw speed for bulk density; pomace proportion and temperature for water absorption index and water solubility index, pomace proportion, screw speed and temperature for hardness and screw speed for sensory score. The compromised optimum condition obtained by numerical integration for development of extrudates were: carrot pomace of 11.75% in rice flour, moisture content 19.92%, screw speed 249.1 rpm and die temperature 114.3°C. Sensory evaluation revealed that carrot pomace could be incorporated into ready-to-eat expanded products upto the level of 11.75%.

Modeling and Characterization of Blended Guava Pomace and Pulse Powder Based Rice Extrudates

The purpose of the present work was to study the effect of guava pomace and pulse powder incorporation in to rice based extrudates on physical characteristics. Guava pomace collected after juice extraction was dried and milled. It was then added with pulse powder-rice flour blend at different combinations based on Central Composite Rotatable Design (CCRD). The independent variables were moisture content (17 – 21%), temperature (115 – 135°C), screw speed (230 – 270rpm), and varying proportion of rice, pulse and guava pomace. Higher feed moisture content resulted in extrudates with a higher density, lower expansion, higher water absorption index, lower water soluble index, and higher hardness. Higher barrel temperature resulted in reduced density, increased expansion, and water solubility index. Addition of guava pomace resulted in increase in water absorption index, hardness and decreased bulk density, expansion and water solubility index. The study suggested the guava pomace may be utilized up to the level of 10% to in Ready to Eat Snacks.

Colour kinetics and storage characteristics of carrot, pulse and rice by‐product based extrudates

Purpose – The utilisation of food waste/by‐products helps to increase produce recovery and enhances nutrition in low‐cost food without any appreciable increase in product cost. The storage behaviour of the product must be studied before commercialisation of the product. This paper aims to focus on this process.Design/methodology/approach – Extrudates (25 g) prepared under optimised conditions of proportion (rice flour, pulse powder and carrot pomace), moisture content, screw speed and die temperature, were sealed using a polythene sealing machine in LDPE bags and aluminium laminated LDPE bags. The bags were then stored for six months in an incubator at temperature of 38±2°C to evaluate the stability of the product. The extrudates were analysed for change in colour, hardness, moisture content and sensory characteristics.Findings – Zero‐ and first‐order models were fitted for prediction purposes. The minimum overall change in color ΔE value, minimum increase in moisture content and minimum increase in hardn...