Vacuum drying and low-pressure superheated steam drying (LPSSD) of Indian gooseberry flake (used to prepare Indian gooseberry tea) were carried out at various drying conditions to monitor the drying kinetics and quality degradation of the product during drying. In terms of drying kinetics, the vacuum drying took shorter time to dry the product than LPSSD at every drying condition. In terms of quality, it was found that only the product subjected to vacuum drying at 75 °C and absolute pressure of 7 kPa had similar level of ascorbic acid retention compared to those samples of LPSSD at every condition. The total color difference of this sample was, however, slightly higher than that of product dried by LPSSD. Nevertheless, since the color changes were not of much concern to the consumers of Indian gooseberry tea, vacuum drying at 75 °C and 7 kPa was proposed as the most favorable condition for drying of Indian gooseberry flake in terms of energy consumption.

Effects of drying methods and conditions on drying kinetics and quality of Indian gooseberry flake

This study investigated the effects of three drying methods (open sun drying, visqueen-covered solar dryer and polyethylene-covered solar dryer) on b-carotene and vitamin C content of edible portions of mango fruit (Mangifera indica) and cowpea leaves (Vigna unguiculata). Commercial samples were analysed for vitamin C by titrimetry and b-carotene by spectrophotometry at 450 nm. Differences in vitamin retention and loss associated with the three drying methods were assessed by analysis of variance and least significant difference (LSD) at (p<0.05. The fresh cowpea leaf b-carotene and vitamin C content was 140.9 and 164.3 mg / 100g DM respectively and decreased (p<0.05) with drying. Open sun drying method caused the greatest b-carotene and vitamin C loss (58% and 84% respectively), while the visqueen-covered solar dryer caused the least loss (34.5% and 71% respectively). Blanching cowpea leaves improved b-carotene and vitamin C retention by 15% and 7.5% respectively. The b-carotene and vitamin C content of fresh ripe mango fruit was 5.9 and 164.3 mg/100g DM respectively. Similar to effects on cowpea leaves, the mango micronutrient content decreased (p<0.05) with drying. The open sun drying method caused the greatest b-carotene (94.2%) and vitamin C (84.5%) loss, while the visqueen-covered solar dryer caused the least (73 and 53% respectively). These results show that the three solar drying methods cause significant loss of pro-vitamin A and vitamin C in dried fruits and vegetables. However, open sun drying causes the most loss and the visqueen-covered solar dryer the least, making the later a probable better drying technology for fruit and vegetable preservation. The drying technologies should be improved to enhance vitamin retention.

/pdf/alterations-in-fruit-and-vegetable-beta-carotene-and-vitamin-1q87fcey9g.pdf

Alterations in fruit and vegetable beta-carotene and vitamin C content caused by open-sun drying, visqueen-covered and polyethylene-covered solar-dryers.

Handbook of poultry science and technology , Handbook of poultry science and technology , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Handbook of poultry science and technology

Microencapsulation of vitamins in food applications to prevent losses in processing and storage: A review.

The micronutrients in many cellular processes, riboflavin (vitamin B2), FMN, and FAD are photo-sensitive to UV and visible light to generate reactive oxygen species (ROS). The riboflavin photochemical treatment with UV light has been applied for the inactivation of microorganisms to serve as an effective and safe technology. Ultra-violet or high-intensity radiation is, however, considered as a highly risky practice. This study was working on the application of visible LED lights to riboflavin photochemical reactions to development an effective antimicrobial treatment. The photosensitization of bacterial genome with riboflavin was investigated in vitro and in vivo by light quality and irradiation dosage. The riboflavin photochemical treatment with blue LED light was proved to be able to inactivate E. coli by damaging nucleic acids with ROS generated. Riboflavin is capable of intercalating between the bases of bacterial DNA or RNA and absorbs lights in the visible regions. LED light illumination could be a more accessible and safe practice for riboflavin photochemical treatments to achieve hygienic requirements in vitro.

Blue light induced free radicals from riboflavin on E. coli DNA damage

Vitamins are one of the few groups of food constituents in which it is possible to demonstrate quantitatively a deterioration in content over a period. The rate of this reduction in vitamin content is influenced by a number of factors: 

1.

Temperature




2.

Moisture




3.

Oxygen




4.

Light




5.

pH




6.

Oxidising and reducing agents




7.

Presence of metallic ions (e.g. iron, copper)




8.

Presence of other vitamins




9.

Other components of food such as sulphur dioxide




10.

Combinations of the above.

P. Berry Ottaway

Papers

Stability of vitamins in food