Development of an inflatable solar dryer for improved postharvest handling of paddy rice in humid climates

Rice is the staple food for more than three billion people worldwide.Although considerable progress has been made with respect to improved breeds and production practices,losses during postharvest handling remain considerable.Drying and storage of paddy are two key stages where management can be improved.For rice,grain moisture content of 14%prevents microbiological activity,while a level of about 12%minimizes quality losses over prolonged storage periods.Due to the need for simple and economical technologies,an inflatable solar dryer(ISD)was developed based on adaptations of the Hohenheim-type solar tunnel dryer.To form a drying tunnel,transparent polyethylene(PE)film attaches by zipper to a reinforced black polyvinyl chloride(PVC)film.To reduce heat loss,a flexible multilayer floor was used along the drying area.The tunnel does not need a substructure as it is stabilized adequately from pressure created by two axial flow ventilators.During experiments,paddy was spread on the floor and mixed with a special roller bar.The ISD has been evaluated for paddy in the Philippines during both rainy and dry seasons and was subsequently optimized.Sun drying and shade drying were carried out in parallel for comparison and product was evaluated for moisture content and quality in terms of milling recovery and head rice yield.Moisture content was reduced from 23%to 14%within 26-52 h of continuous operation during the rainy season and 16%to 14%within 4-26 h of drying during the dry season.In both seasons,the final moisture content of 12%was reached after prolonged drying periods.Quality was not found to be affected with respect to drying treatment.The ISD showed advantages over sun drying,despite longer drying periods.

Hygienic Production and Post-Harvest Handling Practices of Raw Camel Milk in Degahbour District of Jarar Zone, Somali Regional State, Ethiopia

A cross-sectional study was carried out to assess hygienic production and postharvest handling practices of raw camel milk in Degahbour district. The survey studies were based on a total of 120 (2 production systems * 2 rural kebele * 30 households) milk producers, which were selected from Degahbur district using stratified sampling technique. Data from the selected producers were collected using questionnaire survey and field observation. The results showed that the majority of the sampled household heads in pastoral (93.3%) and agro-pastoral (76.6%) production systems were illiterate. Moreover, none of the respondents in the study area had training on hygienic milk production and postharvest handling practices. The study result also indicated that none of the respondents in the study area washed the udder of milking camel before milking. Moreover, only 6.6% of pastoralists and 25% of agro-pastoralists wash their hands before milking. Equipment made of wooden materials are mainly used for milking, whereas, plastic jerry-cans were most commonly used for storage. About 45% of the pastoralists and 81.6% of the agro-pastoralists were cleaning milk vessels regularly;however, majority of the respondents both production systems were using water from non-tap sources for hygienic practices. Bosciaminimifolia, Acacia ethaica and Blanitesgalabra were the most commonly used plant species for smoking in the study area. Therefore, hygienic production and postharvest handling practices should be followed to improve the quality and suitability of camel milk for its intended use in the study area.

Amylolytic Activity in Selected Sweetpotato(Ipomoea batatas Lam)Varieties during Development and in Storage

Sweetpotato varieties (five) were investigated for changes in α- and β-amylase activities during root development and on subjection of harvested roots to different postharvest handling and storage conditions. Changes in α- and β-amylase activities in development were monitored from 10 weeks after planting. At physiological maturity, sweetpotato roots were harvested and subjected to various conditions: freshly harvested roots and cured roots (spread under the sun for four days at 29℃ - 31℃ and 63% - 65% relative humidity), stored at ambient conditions (23℃ - 26℃ and 70% - 80% relative humidity) and in a semi-underground pit (19℃ - 21℃ and 90% - 95% relative humidity). Generally α- and β-amylase activities increased during development with NASPOT 9 and 10 consistently registering the highest activities and NASPOT 1 the lowest activity. Generally, maximum α-amylase activities were achieved at week 3 in ambient stores for NASPOT 9 and NASPOT 10 at 0.930 and 0.897 CU/g, respectively. Maximum β-amylase activity was achieved in ambient stores at week 3 and 4 for fresh and cured NASPOT 9 at 806 and 782 BU/g, respectively. Generally, curing and storing sweetpotatoes in ambient conditions registered the highest amylase activity. Maximum α- and β-amylase activities were registered at 67℃ - 68℃ and 58℃ - 60℃, respectively. These findings provide information for controlled modification of amylase activities of these sweetpotato varieties for product development efforts and monitoring the shelf life of the roots during storage.