The effects of postharvest treatment and chemical interactions on the bioavailability of ascorbic acid, thiamin, vitamin a, carotenoids, and minerals

Abstract

All recent health recommendations include admonitions to reduce calories, maintain desirable weight, reduce fat, increase complex carbohydrates, and ensure an adequate intake of nutrients. Such recommendations require that we know not only nutrient composition of foods, but also potential losses and decreased bioavailability due to postharvest treatment and chemical interactions. This article discusses in some detail the reactions of concern that cause such changes and their potential alleviation with several key nutrients. The nutrients discussed were chosen as a result of the conclusions of the Joint Nutrition Monitoring Report of the Department of Health and Human Services and the U.S. Department of Agriculture. Obviously other choices could have been made, but the authors felt that the nutrients chosen--ascorbic acid, thiamin, vitamin A, carotenoids, calcium, and iron--were representative of a key profile of nutrients whose reactivity makes them vulnerable to losses in bioavailability, as well as being noted in the Joint Nutrition Monitoring Report.

Effect of dehydration methods on retention of carotenoids, tocopherols, ascorbic acid and antioxidant activity in Moringa oleifera leaves and preparation of a RTE product

“…A number of dehydration procedures are employed for fruits and vegetables, i.e., sun-, cross flow-, drum-, spray-, puff-, freeze-and microwavedrying (Chong and Law 2010). For most vegetables, drying resulted in 10-20 % loss of carotenoids (Clydesdale et al 1991), with the increased surface area of dried or powdered products leading to further losses (through autoxidation) unless they were protected from air and light. Specially, dehydration (heating) cause significant quantitative changes in carotenoid isomers, which was also observed in present investigation.…”

Thiamin (vitamin B1)

“…The effects of chemical interactions on thiamin stability in complex food systems has been reviewed (Clydesdale et al, 1991). The major form of thiamin in meat products is protein-bound thiamin pyrophosphate (TPP).…”

Variation in moisture, total sugar, and carotene content of Japanese carrots: Use in sample size determination

“…bCarotene content is reported to increase during storage (Brown, 1949;Clydesdale et al, 1991;Lee, 1986;Rygg, 1949), and some of the samples obtained in February for this study were storage samples. Hochmuth et al (1999) reported that b-carotene concentrations are influenced by nitrogenous fertilizers.…”