Studies on the effect of microwave (MW) heating on Bitter melon (Momordica charantia).

Patil, Amitkumar. S (2014) Studies on the effect of microwave (MW) heating on Bitter melon (Momordica charantia). [Student Project Report] (Submitted)

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Abstract

Bitter gourds are among the fruits with the highest levels of active constituents alkaloids,glycoside, peptides, acids, cucurbitins, charantin, cucurbitacins, momordine, momorcharinsand proteins. It contains lots of nutritional and medicinal factors. An experimental investigation was carried out with five different blanching methods by using microwave (MW) heating system. In microwave blanching bitter gourds were exposed to 900w power scale at different wattage level. The first objective of this study was to employ microwave blanching (instead of conventional blanching) during blanching and investigate its effect on proximate content and quality attributes (texture, colour, proximate content) of bitter gourds. Bitter gourds were subjected to 1.conventional blanching 2. Blanching in 5% Salt. 3. Microwave exposed hot water blanching 4. Microwave exposed salt water blanching 5. Microwave heating at 900w power scale with different wattage levels. In each method bitter gourd slices were treated with 1,2,3 min time duration at 70°,80°,90°c temperature . In microwave heating 2w/g, 3w/g, 4w/g, 5w/g for 1, 2, 3 min on 900w power scale . After each blanching process quality characteristics (pH, °°Brix, total acidity, reducing sugars, colour, minerals, microbial flora, pectinmethylesterase (PME) activity, PPO activity ,POD activity ) of blanched bitter gourd were analysed. All the parameters of proximate, texture, colour analysis of microwave treated samples were compared with fresh and other treated bitter gourds. Microwave blanching at 4 W/gm for 2 min and 5 W/gm for 1 min heating have shown the hardness as fresh, similarly 5 % of salt water followed by microwave heating at 70 OC 2 min and 90 OC 1 min is near to fresh.There was no color changes by microwave blanching, but in other treatments a lot of variance in L*, a* and b* values were found when compared to the fresh. The optimized microwave blanching at 4 W/gm for 2 min and 5 W/gm for 1 min shown the proximate composition similar to fresh. The total chlorophyll value (mg/L) of fresh was 2.8642 whereas microwave blanching at 2 W/gm for 1 min 4 W/gm for 2 min and 5 W/gm for 1 min heating was found to be 2.8442 , 2.5565 and 2.3995 respectively. PME activity at 4 W/gm for 2 min and 5 W/gm for 1 min was reduced from 16.14 PME units (fresh) to 1.3 and 0. 86% of inhibition and 97.3 % of inhibition of POD activity was found in 4 W/gm for 2 min and 5 W/gm for 1 min respectively. xi The second objective of the study was microwave drying. Differently blanched bitter gourds were dried for the purpose of the study drying model. Bitter gourds were exposed at 900w power scale for 30 sec on 30 sec off microwave exposing technique. Higher moisture removal rate was found in MW heating directly irradiated at 5 W/gm for 2 min.Out of 11 optimum drying models, Weibull distribution was found to have a constant of a= 0.0657, b= -1.0541, k= 0.0899, n= 1.2366 R2= 0.9993 for 5 W/gm 2 min sample. Hue and chrome values of MW dried samples of 4 W/gm and 5 W/gm were near to the fresh values of -80 o and 25.52.The work carried out for blanching and drying of bitter gourd optimized for proximate analysis, colour values, enzyme inactivation, texture and drying was found to have an insignificant variation by using MW blanching and drying. So it was found that there is no effect of microwave heating on blanching but the drying rate will be faster when compared to conventional drying.

Item Type:	Student Project Report
Uncontrolled Keywords:	Bitter gourds, blanching methods, microwave (MW) heating system
Subjects:	600 Technology > 08 Food technology > 23 Vegetables 600 Technology > 08 Food technology > 06 Preservation and Storage > 02 Drying and Dehydration
Divisions:	CFTRI Resource Centres > Hyderabad
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	23 Jun 2015 11:57
Last Modified:	23 Jun 2015 11:57
URI:	http://ir.cftri.res.in/id/eprint/11878

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