Thermal oxidation of methyl oleate was studied over a range of temperatures from 50 C to 150 C for periods of time up to 30 min. Degradation was quantitatively followed by gas liquid chromatography (GLC) and liquid scintillation counting of the products of methyl oleate-U-14C heated under a stream of...
Studies involving freeze-dried methyl linolenate-gelatin foams indicate that the extent of lipid-protein interaction corresponds to the degree of autoxidation of the lipid fraction. It appears that approximately 11% of the malonaldehyde as defined by the 2-thiobarbituric acid test is firmly bound to the protein. The induction period of autoxidation is...
Pesticide chemists have recognized since the 1940's that ultraviolet light was deleterious to the insecticidal properties of certain compounds. However, it has been only within the last 15 years that a number of photodecomposition products of the chlorinated hydrocarbon
insecticides have been isolated and identified. The degradation of insecticides by...
A threshold pattern for the even-numbered free fatty acids (FFA) in butter depended on chain-length. Butyric acid had the lowest total average flavor threshold (AFT) of the more volatile FFA, and the total AFT values increased as chain-length increased through hexanoic and octanoic acids. A soapy after-taste predominated at and...
Eighty-one microbial species isolated from seafoods and other marine sources were examined to determine the extent of interactions among these species. Spot-plates, cross-plates, and concurrent growth experiments at 7, 15, 20, and 30 C indicated that Lactobacillus species were capable of inhibiting other microorganisms. Lactobacillus species isolated from oysters and...
We have studied commercial fermentation practices for three vintages in order to learn how they affect
extraction and stability of anthocyanin pigments and other phenolic compounds in Pinot noir. Wines
were monitored during fermentation, processing, and aging for anthocyanin and phenolic content, color
intensity, and for phenolic profiles using high...
Over the last several years 'stuck' and 'sluggish' fermenations have become a ma or concern of winemakers in Oregon as well as in Washington and California. During the 1996 vintage we began a preliminary survey of Oregon musts and juices at harvest and showed that many were low or marginal...
Nisin, bacteriocin produced by Lactococcus lactis, Nisin may have the potential to replace (or reduce) sulfiting agents traditionally added to wines to prevent the growth of spoilage lactic acid bacteria. This may be valuable since sulfites are believed to cause toxic responses in sensitive individuals. As a result, the U.S....
Nisin, a bactericidal polypeptide, has the potential to inhibit spoilage bacteria and control rnatolactic fermentation in wines. Nisin activity has previously been observed to remain stable in white wines but to decrease in red wines. This decrease is believed to be directly proportional to the concentration of polyphenolic compounds in...
Hydrogen sulfide and related sulfur compounds produced internally by yeast during fermentation are considered highly undesirable if they are excreted and exceed threshold concentrations in the finished wine, as they cause an unpleasant "reduced character". The threshold for hydrogen sulfide is on the order of parts per billion and that...