Developing partially dehydrated pineapple products using solar drier

Abstract

The present investigation was undertaken to study the efficiency of solar drier as against open sun drying in the partial dehydration of the pineapple products.

Assessment on the moisture content and weight loss, PH, acidity, reducing sugar and Vitamin C revealed that there was a negligible difference in the moisture content of the samples dried under two different methods. The weight loss of the product were also found to be almost same for both solar dried as well as the sun dried samples.

The PH of the dried pineapple products was found to be increased after the dehydration while the acidity was reduced. The reducing sugar content was also reduced in dried samples. But more reduction in acidity and reducing sugar was found in sun dried samples than in the solar dried samples. A drastic destruction of Vitamin C content was noticed after the dehydration, in the dried products subjected to different storage conditions.

Assessment of the organoleptic qualities indicated that the solar dried samples were proved to be best with respect to its various quality attribute tests. Only in appearance and colour attribute tests, the sun dried samples showed better scores than that of solar dried ones. Among the various pretreatments applied, the sulphur fumigated samples scored the highest in all the quality attribute tests.

Periodical evaluation of the changes in the acidic content showed that there was a slight decrease in the acidity throughout the storage periods in most of the samples, which in turn proved that the storage periods had an influence on the changes in acidic content of the products. Analysis of the changes in PH content indicated a slight increase during the storage.

Monthly analysis of the changes in the reducing sugar content revealed a gradual increase in all the samples from both solar drying sun drying throughout the storage periods of four months. Among the different pretreatments, the sulphur fumigated samples was found to contain higher reducing sugar content. Not much difference was noticed in the reducing sugar content, with drying methods and storage periods.

Periodical assessment of the changes in the organoleptic qualities during the storage periods of four months revealed that only the solar dried sulphur fumigated samples scored highest in all the months of storage with respect to different quality attributes. The organoleptic scores of quality attribute tests showed a decrease only during the fourth month of storage. The storage periods and drying methods also had an influence over the organoleptic qualities of the processed products.

Microbial assessment revealed that Bacillus species, Aspergillus species and yeast were identified as micro organisms in all the dried products after a period of four months.

The cost benefit analysis revealed that the price of different products ranged between Rs.13.85/- and Rs.15.75/- and there is not much difference in the cost of products undergone different pretreatments and drying methods.

The above findings clearly indicated that pineapple fruits can be processed efficiently using solar drier. This investigation also revealed that sulphur – fumigation was best to apply as pretreatment prior to dehydration. In general, the solar dried samples proved to be best both qualitatively and organoleptically.