Suitability of osmotic drying technique for product development in jack fruit(Artocarpus heterophylus Lam)

Abstract

The study entitled “Suitability of osmotic drying technique for product development in jackfruit artocarpus hetrophyllus lam is a comprehensive study aimed at standardization of osmotic drying technique for product development in jackfruit varieties namely soft flesh type and firm flesh type and its evaluation on organoleptic and shelf – life qualities.

Results of the study indicated that weightloss of the products were found to be 7.0 to 15.7 percent in firm and in soft flesh variaties of jack fruit and moisture loss was accounted to be 9.0 to 9.6 percent in soft flesh variety and 8.7 to 9.6 percent in firm flesh variety.

The effect of pretreatment on weightloss and on moisture content indicated that pretreatments like preservative sucrose concentration, temperature and immersion time postitively influence the percentage of weightloss, but not found to influence the moisture levels in the final product. It was also observed that there was no significant difference in the moisture content and weight loss between the two varieties of jackfruit.

The time taken for drying the differently treated products of both varieties ranged between 42 to 58 hours. It was also noted that preservative used had no effect on drying time but the samples treated with highest of sugar concentration and temperature used were found to take the lease time for drying.

Assessment of chemical components indicated that in fresh jackfruit the acidity was 2.34g in soft flesh samples and 2.32g in firm fresh samples, and it was reduced to 0.48g and 0.43g respectively in dried samples.

Reducing sugar of fresh jackfruit was 4.39g in soft flesh samples and 4.40 in firm flesh samples and was reduced to 1.52 and 1.54 respectively in dried samples. The Vitamin C content of fresh jackfruit was 7mg in both varieties where as in dried products, vitamin C was reduced to traces.

It was also noted that firm flesh samples were less acidic than soft flesh samples, but there was no significant difference between the two varieties in acidity content. During storage, acidity was found to decrease in the dried jackfruit products.

Firm flesh samples had more reducing sugar content than soft flesh samples. Storage was found to positively influence the reducing sugar level of the dried jackfruit products.

Assessment of the organoleptic qualities of the dried jackfruit products revealed that samples treated with the preservative sodium metabisulphate along with 20 percent glycerol showed highest acceptability with respect to appearance flavor, colour, taste and texture. Firm flesh samples showed higher scores than soft fresh samples at different preservative levels and it was observed that samples immersed for 30 minutes secured better scores in quality attributes than the samples immersed for 60 minutes.

Effect of the temperature on the quality of products indicated that a temperature of 700C is more suitable than the lower temperature for pretreatments in two varieties of jackfruits before drying.

Impact of different sugar concentration tried (600 Brix and 700Brix ) in the study revealed that samples treated with 600Brix sugar concentration retained better appearance, colour and texture.

The products showed a shelf stability of five months after which microbial infestation was detected in the sample.

Impact of pretreatments on changes in the quality parameters indicated a significant difference in samples treated at different preservative levels through out the storage period in all quality attributes.

Immersion time was not found to affect the quality attributes during storage however temperature influenced the quality attributes during storage. Samples treated with 600Brix sugar solution retained better organoleptic qualities than the samples treated with 700 Brix sugar solution.

Among the various pretreatments applied in the present study, the pretreatment 60 minute immersion time, 700 temperature, 600Brix sugar concentration and preservative (Sodium metabsilphate (0.4 percent ) along with 20 percent glycerol) proved to the best treatment for the quality retention in the stored jackfruit products though storage decreased the overall acceptability.

Consumer acceptance of the products revealed that among the thirty-six treatments tries in the study in the soft flesh variety, the samples treated with 70 percent sugar solution heated to 500C and immersed for 30 minutes with preservative level 20 percent glycerol was adjudged to be the best product but in the firm flesh variety, samples given same treatment but without having any glycerol was proved to be the most acceptable product.

Cost of the products of firm flesh samples ranged from Rs.16.30 to 18.10 per kg and in soft flesh samples, it ranged between 12.30 to 14.10perkg. Thus dried jackfruit products utilizing soft and firm flesh varieties, which are nutritious, affordable and acceptable to the consumer can be prepared for consumption.