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Candida molischiana 35M5N β-glucosidase was immobilized to Duolite A-568 resin. Higher immobilization efficiency (86%) was achieved with citrate−phosphate buffer (0.1 M) at pH 4. The study of the immobilized β-glucosidase demonstrated that the physicochemical properties were similar to those of the free enzyme. Free and immobilized β-glucosidase were used to treat muscat wine and apricot fruit juice. GC−MS analysis indicated a significant increase in the flavor compounds nerol, geraniol, linalool, 2-phenylethanol, and benzyl alcohol in the muscat wine and linalool, α- and γ-terpinene, α-terpineol, 2-phenylethanol, and α-pinene in the apricot fruit juice. The immobilized β-glucosidase was found to be very stable under fruit juice or wine conditions and could be used repeatedly for several hydrolyses of bound aroma. The efficiency of this experimental catalyst was successfully tested with several fruit juices and wines containing various amounts of precursors. Keywords: Wines; fruit juices; aroma precursors; β-glucosidase; immobilization

Lipid content and composition of fatty acids with 6-25 carbon atoms were studied on strains of the 13 pink or red yeast species belonging to the genus Rhodotorula. The total amount of lipid represented an average of 13% of the dry weight. The neutral and polar lipid fractions were analyzed separately. For all the strains studied, the major fatty acids in both fractions were oleic, linoleic and palmitic acids, which formed 80% of the total number of fatty acids. A notable amount of arachidonic acid, a precursor of eicosanoid hormones, was found in R. acheniorum, R. aurantiaca and R. bacarum. Depending on the strain, 1-10 carotenoid pigments were detected; beta-carotene was always the major carotenoid present.

The present work reviews the numerous nitrile compounds that have been isolated from plants and animals. Two kinds of potentially toxic molecules are widespread, namely the cyanogenic glycosides and cyanollpids. Many other aromatic and allphatic nitriles are synthesized to a lesser extent. Different studies on the synthesis and degradation of these cyanogenic compounds are also reviewed to emphasize the potential use of different microorganisms for the detoxification of food and foodstuff.

The lactic acid bacterium, Leuconostoc mesenteroides, when grown on an arbutin‐containing medium, was found to produce an intracellular β‐glucosidase. The enzyme was purified by chromatofocusing, ion‐exchange chromatography and gel filtration. The molecular mass of the purified intracellular β‐glucosidase, as estimated by gel filtration, was 360 kDa. The tetrameric structure of the β‐glucosidase was determined following treatment of the purified enzyme with dodecyl sulphate (SDS). The intracellular β‐glucosidase exhibited optimum catalytic activity at 50°C and pH 6 with citrate–phosphate buffer, and 5·5 with phosphate buffer. The enzyme was active against glycosides with (1→4)‐β, (1→4)‐α and (1→6)‐α linkage configuration. From Lineweaver–Burk plots, Km values of 0·07 mmol l−1 and 3·7 mmol l−1 were found for p‐nitrophenyl‐β‐D‐glucopyranoside and linamarin, respectively. The β‐glucosidase was competitively inhibited by glucose and by D‐gluconic acid–lactone and a glucosyl transferase activity was observed in the presence of ethanol. The β‐glucosidase of Leuconostoc mesenteroides, with cyanogenic activity, could be of potential interest in cassava detoxification, by hydrolysing the cyanogenic glucosides present in cassava pulp.

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A decade or so ago, there was considerable interest in developing single cell protein production from raw materials. Many factors have influenced the development of fodder yeast technology, notably the biochemistry and physiology of the yeast. It is shown that those considerations have led to the choice of a continuous fermentation technology.