In this study, the microwave (MW) roasting (MWR) of peanuts ( L.) is attempted, optimized and compared with conventional drum roasting. A two factor/three level face centered composite design based MWR experiments was conducted at different roasting time (60, 180 and 300 s) and MW power levels (180, 540 and 900 W). The roasting quality was analyzed by physicochemical and sensory attributes of roasted peanuts and extracted oil viz., moisture loss, hardness, browning index (BI), induction period (IP) based on Rancimat, peroxide value (PV) and overall acceptability (OA), respectively. A roasting time and MW power dependent improvement in the desired quality of roasted peanuts and extracted oil was observed attributable to the formation of antioxidant Maillard reaction compounds. A second order polynomial model adequately described the roasting experimental data ( < 0.0001, > 0.90) with an insignificant lack of fit ( > 0.05). Using response surface methodology, the MWR was optimized at roasting time of 201 s and MW power level of 900 W which yielded favorable values of quality attributes (moisture loss, 3.06%; hardness, 4528.34 g; BI, 58.89; IP, 8.12 h; PV, 8.80 milliequivalents O/kg; OA, 6.40). Furthermore, the quality assessment of ground peanuts for selected time-power combinations (low, optimum and high roasts) was attempted using scanning electron microscopy, electronic nose and Fourier transform infrared spectroscopy which revealed better quality of optimized MWR peanuts.

Physical and thermal properties of roasted Bengal gram flour of varying particle sizes were determined as a function of moisture content. As the moisture content increased from 3.19 to 13.06% (w.b.), the bulk density, true density, thermal conductivity, specific heat and thermal diffusivity of roasted Bengal gram flour of particle sizes of 212, 180 and 150 μm increased from 0.52 to 0.77 g/cm 3 , 1.45 to 1.52 g/cm 3 , 0.0930 to 0.151 W/m/K, 1.052 to 1.816 MJ/m 3 /K, and 0.089 to 1.00 mm 2 /s, respectively. The flowability ranged from 16 to 21 s over similar moisture content and particle sizes. The significant variation occurred in physical and thermal properties due to heterogeneity of the molecular size of different particle sizes and level of moisture content. PRACTICAL APPLICATIONSThe resulted data of roasted Bengal flour offer a great potential for researcher and industrialists for new product formulation and design. Moisture and particle size were changed during storage and operations, so these studies might be helpful for finding out energy balance, improving energy requirement and storage facility. The methods are quick and convenient for determination of physical and thermal properties to any other methods.

No abstract

Ready-to-eat wheat grits are highly fibrous food product which was prepared from wheat by using different thermal treatments (Parboiling, pressure parboiling and roasting methods). The effects of these treatments on hardness, alkali spreading value (ASV), granular morphology, protein digestibility (PD), grit yield, grinding constants and specific power consumption (SPC) were studied. However, the particle size distribution, grinding constants and SPC were also studied with the different feed rates of each experiment. The maximum grits yield (77%), SPC (0.061 kWh/kg), hardness (6.67 kg), were found in pressure parboiling. The highest PD (78 %) and ASV were observed in roasting method. Although, a significant variation was found in grinding constants with the different feed rates and heat treatments. The roasting method was found to have overall desired values of PD (78%), granular morphology, ASV (7), hardness (3.21 kg) and SPC (0.040 kWh/kg). PRACTICAL APPLICATIONSReady-to-eat wheat grits are highly fibrous food product and prepared from wheat by using different thermal treatments. It plays an important role in addressing the constipation problems. The power consumption and product quality are key parameters for producer and consumer. This study has generated sound thermal processing and energy consumption data and health benefits which can be used by food industries and consumers.

Soybean (Glycine max L.) is a popular oil crop, used in traditional cooking by Asian people and commercially processed to produce edible oil and protein meal. The protein meal is used in wheat flour fortification, bakery products, and soy nuggets, whereas the edible oil is largely consumed in cooking and frying (de Oliveira Silva & Perrone, 2015; Raigar & Mishra, 2018). The other value-added products consumed worldwide produced from soybean are soy flour, soya milk, tofu, etc. (Navicha, Hua, Masamba, & Zhang, 2017). The use of soybean sometime imparts beany taste to the product which negatively affects the acceptance of soy foods among consumers. Roasting process can be used to countered this issue (Shin, Kim, & Kim, 2013), which involves heating of soybeans using dry hot medium at 160-200°C depending on the installed equipment and duration of heating (Raigar & Mishra, 2018). Various methods of roasting such as rotary drum, heated ceramic roasting, and salt bed roasting are commonly used (Chauhan, Chauhan, Sharma, Bajpai, & Yadav, 2003; Tulashie, Appiah, Akpari, & Saabome, 2020). Use of direct and indirect fire in the roasting process varies the degree of heating, and thereby the product quality. Being a high-temperature short time method, roasting induces desirable, and undesirable quality changes in the kernels (Schoeman & Manley, 2019). It is a popular grain processing method used worldwide for the different roasting products with improved taste, color, aroma, texture, palatability, digestibility, and sen