Problems in Measuring Leucoanthocyanin Content of Pears

Abstract

SUMMARY— Four solvents, 95% ethanol, methanol, and both ethanolic and aqueous acetone, were used to extract leucoanthocyanin from Bartlett pears. Ethanol extracted approximately one‐fourth, methanol one‐third, and acetone somewhat less than two‐thirds, based on the amount in the corresponding slurry. Conversion of leucoanthocyanin to anthocyanidin was influenced by the dispersing medium, the normality of the butanol in which the conversion was effected, and the source of the leucoanthocyanin (pear mart, slurry, or synthetic leucocyanidin). When ethanolic acetone was the dispersing medium, yields of anthocyanidin were greatest. Developer acidified to a normality of 0.025 compared to 0.6 reduced phlobaphene formation and gave higher yields of anthocyanidin except in the case of pear mart previously extracted with 70% ethanol and then dispersed in acetone. When conversion was effected at a normality of 0.025, yield of anthocyanidin from the mart of pear in acetone was somewhat less than half that obtained when ethanol was the dispersing' medium, that from the slurry was 25% greater, and the yield from synthetic leucocyanidin was almost twice as great.

Effect of stress on growth, pigment production and morphology of Monascus sp. in solid cultures

“…The increased production of pigments in the presence of NaCl could be due to an osmoprotective role of pigments in the organism. As salt reduces water activity considerably, the response of the fungi towards salt stress is governed by the demands imposed on the water activity by the organism (Ingram and Kitchell 1967).…”

Influence of Ozone, Hydrogen Peroxide, or Salt on Microbial Profile, TBARS and Color of Channel Catfish Fillets

“…Success of salt, which is probably the most widely used food preservative, depends on the fact that it inhibits objectionable putrefaction and pathogenic microorganisms (Ingram and Kitchell 1967). Ascorbic acid can retard microbial growth and has been shown to increase the refrigerated shelf-life of cut-up broiler parts (Arafa and Chen 1977).…”

Variations in the composition of the flora on a Wiltshire cured bacon side

“…This will be reflected in the water activity of the food. A brine concentration in bacon exceeding about 5% will exclude the normal pork spoilage flora, Pseudomonas, but permit the growth of the Micrococcus (Ingram & Kitchell, 1967). O n the basis of a, it could be postulated that the musculature of bacon would have a higher value than the skin and thus explain the apparent increasing importance of Acinetobacter spp.…”