Optimization of process parameters for osmotic dehydration of papaya cubes.

Process temperature (30, 40 and 50 °C), syrup concentration (50, 60 and 70(o) Brix) and process time (4, 5 and 6 h) for osmotic dehydration of papaya (Carica papaya) cubes were optimized for the maximum water loss and optimum sugar gain by using response surface methodology. The peeled and pre-processed papaya cubes of 1 cm size were immersed in sugar syrup at constant temperature water bath having syrup to papaya cubes ratio of 4:1 (w/w). The cubes were removed from bath at pre-decided time, rinsed with water and weighed. Initial moisture content of papaya samples were 87.5-88.5% (wb), which was reduced to 67.6-81.1% after osmotic dehydration in various experiments showing mass reduction, water loss and sugar gain in the range of 20.6-36.4, 23.2-44.5 and 2.5-8.1%, respectively. The weight reduction, water loss and sugar gain data were statistically analyzed and regression equation of second order were found the best fit for all the experimental data. Maximum water loss of 28% with optimum sugar gain of 4% was predicted for the 60(o)Brix syrup concentration at 37 °C for syrup to fruit ratio as 4:1 in 4.25 h of osmotic dehydration.

Studies on moisture sorption isotherms for osmotically dehydrated papaya cubes and verification of selected models.

The water desorption properties of osmotically dehydrated papaya cubes at various temperatures were studied by fitting experimental isotherms in Henderson, Oswin, Chen and Clayton and Kuhn equations having 2 parameters and Henderson and Oswin equations were modified to describe the temperature dependence of isotherm data. Oswin equation was useful to predict the equilibrium moisture content values for use in determining the effective moisture diffusion coefficient during subsequent air drying process.

Healing potential of Calotropis procera on dermal wounds in Guinea pigs.

Calotropis procera (Asclepiadaceae) is a well known plant in the Ayurvedic system of medicine. Based on its traditional use this plant was selected for evaluation of its wound healing potential. For this purpose four full thickness excisional wounds of 8.0 mm diameter were inflicted on the back of guinea pigs. Topical application of 20 microl of 1.0% sterile solution of the latex of C. procera twice daily was followed for 7 days. The latex significantly augmented the healing process by markedly increasing collagen, DNA and protein synthesis and epithelisation leading to reduction in wound area. Thus the present study provides a scientific rationale for the traditional use of this plant in the management of wound healing.

Chromosomal aberrations induced in barley by LSD.

Seeds of hulled barley (Hordeum vulgare) were germinated and then treated with LSD. Preparations of squashed root tips stained with Feulgen revealed extensive chromosomal aberrations, most of which were chromosome breaks. Nearly half of the breaks occurred in the region of the primary constriction.