Showing papers on "Grapefruit juice published in 1976"
TL;DR: In this paper, the necessary pasteurization temperature, F and z values for pectinesterase inactivation were developed for three varieties of orange juices and one grapefruit juice.
Abstract: The necessary pasteurization temperature, F and z values for pectinesterase inactivation were developed for three varieties of orange juices and one grapefruit juice. Since common commercial practice involves blending various orange varieties, the recommended conditions are those for the most heat resistant variety. For an FT=1.0 min, the recommended processes are T = 194°F with z = 12.2 for orange juice and T = 186°F with z = 9.3 for grapefruit juice.
131 citations
68 citations
TL;DR: Aspergillus parasiticus was inoculated into grapefruit juice and a glucose-yeast extract medium; both contained 500–7000 ppm of citrus oils that were incorporated into the media by sonication even when the substrate contained a large amount of citrus oil.
Abstract: Aspergillus parasiticus was inoculated into grapefruit juice and a glucose-yeast extract medium; both contained 500–7000 ppm of citrus oils that were incorporated into the media by sonication. Orange and lemon oil were more inhibitory to mold growth and aflatoxin production than was d-limonene, the main constituent of the two peel oils. After 7 days at 28° C, 2000 ppm of lemon and 3000 ppm of orange oil in grapefruit juice afforded maximum suppression of mold growth and toxin formation. When the glucose-yeast extract medium was used, 3000 ppm of either oil were needed to achieve the same result. After 4 days at 28° C, orange oil at 3500 ppm in either medium markedly inhibited mold growth (as evidenced by dry weight of mold mycelium) and aflatoxin production (only 14 and 1% of the amount normally produced in the juice and artificial medium, respectively). Higher concentrations of orange oil further reduced mold growth and aflatoxin production and also delayed the onset of sporulation, if it occurred. Although aflatoxin was detected in all samples, only 0.2 to 0.5% of the amount found in controls (without the citrus oil) was present when the medium contained 7000 ppm orange oil. The mold consistently grew, albeit very poorly, on the glass at the liquid-atmosphere interface even when the substrate contained a large amount of citrus oil.
42 citations
TL;DR: Samples of juice from both early and later season New Zealand grapefruit have been analysed for the presence of three enzymes that have been reported in some overseas citrus varieties; pectinesterase, polygalacturonase and ascorbic acid oxidase were detected.
Abstract: Samples of juice from both early and later season New Zealand grapefruit have been analysed for the presence of three enzymes that have been reported in some overseas citrus varieties. While both early and late season juice contained pectinesterase, neither polygalacturonase nor ascorbic acid oxidase was detected in juice extracted from early or late season fruit.
11 citations