Starch was extracted from potato wastes and its peels to prepare bio-degradable films using glycerol and sorbitol at various concentrations of 35%, 45% and 55 (w/w) of dry starch. The properties of films prepared with modification techniques (hydrothermal treatment (HTT) and acid-alcohol treatment (AAT)) were analyzed. Biodegradability test was done by incubating with amylolytic bacteria (Bacillus lichneformis and Streptococcus bovis) for 24 hours and fungi (Aspergillus niger and Rhizopus stolonifer) for 72 hours. All microbial species were isolated from soil except S. bovis which was from calf stool and identified by conventional methods. The properties of modified starches were significantly different from non-treated starches. Tensile strength (10 N/m2) and elongation (9.47%) were significantly (p<0.05) superior in HTT starch films whereas solubility (25.8%) was superior in AAT starch films.  Elongation (8.91%) and solubility (29.98%) were significantly (p<0.05) superior in 35% and 55% glycerol used films respectively but tensile strength (13.02 N/m2) was superior in 35% sorbitol used films. WVTR (999 g/m2/d) was higher at 91% RH in 55% glycerol used films. Micro-organisms used showed a significant effect (p<0.05) on biodegradation of starch based films. Highest degradation was observed by B. lichneformis i.e, 57.85% while A. niger had minimum of 25.13%. Films prepared with 35% glycerol was significantly (P<0.05) degraded by B. lichneformis i.e, 78.86%. Films prepared by using glycerol with acid alcohol treatment was significantly (P<0.05) degraded by S. bovis (55.57%). Although the starch of same variety of potato waste was not studied, results of the study suggest possibility of preparation of starch based bio degradable films potato waste and its peels by using glycerol and sorbitol.

Tomatoes harvested at four maturity stages (viz. mature-green, breaker, turning and pink) were washed with 100ppm chlorinated water, sorted and ripened at ambient conditions (20-30°C and 76-85% realtive humidity (RH)). The physico-chemical characteristics of unripe and ripe tomatoes were determined.Key words: Chemical characteristics; Harvesting stages; Ripening; Sensory qualityTribhuvan University JournalVol. XXV, No. 1, 2005Page:143-147Uploaded date: 26, September, 2010

The dried roselle (Hibiscus sabdariffa var. sabdariffa) calyces were studied for the extraction of anthocyanin in aqueous solution. The total anthocyanin content in dried roselle powder was found to be 310.48mg/100g of dry matter. The extraction temperature at 70°C gave the highest yield (66.69-70.61%), while at 90°C the degradation of anthocyanins occurred. The solid-liquid ratio revealed no significant effect (p>0.05), whereas the particle size showed a significant effect (p<0.05) on the extraction of anthocyanin. The yields of anthocyanin extraction for 300 and 600 μm particle powders were significantly higher (p<0.5) than that of 1180μm powder. Reduction in the particle size inversely increased the yield of anthocyanins. In conclusion, the extraction of anthocyanin from dried roselle calyces with an average particle size of 600μm using a solid-liquid ratio of 1:50 in aqueous medium with pH 7.0 at 70°C for 20min showed the maximum yield (69.84%). J. Food Sci. Technol. Nepal, Vol. 6 (66-72), 2010 DOI: http://dx.doi.org/10.3126/jfstn.v6i0.8263

on PDF

No abstract

The study aimed to determine the potential of kiwifruit milk clotting enzyme in cheesemaking. The kiwifruit crude enzyme, extracted with sodium phosphate buffer (pH 7.0), was partially purified by 30-80% ammonium sulfate precipitation. 50% ammonium sulfate saturation exhibited maximum milk clotting activity (MCA), along with 1.56 purification fold, and 78.84% activity recovery. From SDS-PAGE analysis, the partially purified protease showed two bands with a molecular mass of 24 kDa and 23 kDa respectively. The optimum conditions (temperature and pH of milk) for a minimum time of coagulation (TOC) and maximum MCA were determined by response surface methodology (RSM). From the numerical optimization study, the optimum conditions for cheesemaking were pH 6.5 and temperature 55oC, having 0.94 desirability. The cheese prepared by kiwifruit protease had significantly (p<0.05) higher moisture, ash, calcium content, and yield than rennet cheese, while significantly (p<0.05) lower fat content and acidity were observed in kiwifruit protease coagulated cheese. However, a non-significant (p>0.05) difference in protein content was obtained between both cheeses. This study highlighted that kiwifruit protease has the ability to be used as an efficient milk clotting enzyme in fresh cheesemaking.

No abstract

Preparation of buckwheat maltSeeds were screened and washed to remove impurities which were adhered with the grain. The cleaned seeds were then steeped in tap water for 12 h to increase the moisture content of the seed( 42-46%). RESEARCH PAPER