Prepration of kharodi sticks using convective and microwave drying
Loading...
Date
2022-01-18
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Vasantrao Naik Marathwada Krishi Vidyapeeth, Parbhani
Abstract
The aim of this study was to prepare a pearl millet Ready-To-Eat (RTE) product Kharodi sticks using convective drying to achieve case hardening to dough sticks and step forward to microwave power to complete drying of sticks. Traditionally Kharodi is prepared manually in the form of chunks and dried in sunshine for 1 to 2 days. Recently few researchers tried to dry chunks/sticks in hot air dryer or sun drying cum microwave drying. Both sun drying and hot air drying are time consuming and sun drying assisted microwave drying still requires open sun shine for few hours which is unhygienic, time consuming and tedious operation. So, to overcome these problems, a combination of convective air drying and microwave drying was selected to reduce the drying time and increases the quality of dried product.
The dough was prepared by cooking pearl millet grits with additional ingredients in boiling water. The cooked dough was cold extruded with the help of hand operated Kharodi extruder on specially fabricated aluminum mesh/ screens in the form of continuous sticks. The wire mesh design helps in uniform exposure of dough sticks to convective air. Preliminary trials were conducted to see the impact of air temperature and drying time to achieve case hardening of the dough sticks. The results revealed that the hot air temperature of 120 OC and case hardening time of 20 min gives effective case hardening with acceptable colour of the Kharodi sticks. The case- hardened sticks were step forwarded to microwave oven for microwave drying on rotating oven plate. The drying experiments were conducted for two independent variables viz., microwave power (MP) and microwave time (Mt) at five levels of 285.44, 360, 540, 720, 794.55 (W) and 5, 10, 15, 20, 25 (min) respectively, in Central Composite Rotatable Design (CCRD). The impact of process parameter on quality attributes of dried product was assessed using responses Moisture content (MC), colour difference (ΔE), hardness (Hd) and crispness (Cr). During experimental trials at design levels of input parameters, the moisture content of dried product ranged from 0.21 to 44.8 percent db after drying, colour difference ranged from 6.14 to 18.35, hardness ranged from 913.81 g to 8356.26 g, and crispness ranged from 0 to 49 (+ peaks). The optimal values of input process parameters obtained from numerical optimization were microwave power (MP) of 540 W, microwave drying time (Mt) of 17 min. The data obtained during experiments was analyse using Response Surface Methodology (RSM). The corresponding optimum responses obtained were moisture content (MC) of 4.70 % (d.b.), colour difference (∆E) of 15.91, hardness (Hd) of 8084.14 g and crispness (Cr) of 39. 81 +peaks. The sensory features of the prepared Kharodi sticks were assessed by a panel of judges for various sensory attributes viz., colour, flavour, taste, and mouthfeel. The data collected from the panellist were evaluated using fuzzy logic to determine the ranking of samples and qualitative attributes of developed Kharodi sticks in general. The three samples prepared were Kharodi sticks with onion slices as Sample 1, prepared Kharodi sticks as a Sample 2 and market Kharodi product as Sample 3. The preference order determined from the analysis of sensorial response data given by the judges was Sample 2 (very good) > Sample 1 (very good) > Sample 1 (medium). Preference order of quality attributes for Kharodi sticks in general was also found as mouthfeel> taste> colour> flavour. From the sensory data, it was found that mouthfeel i.e., texture and taste of dried Kharodi sticks are major quality attributes while flavour is the least important attribute.