J.P. Julien

A Study of the Chemical Composition and Nutritive Value of Leaf Protein Concentrates

Abstract Leaf protein concentrates from alfalfa and from clover obtained by solvent-precipitation and by heat-coagulation have been examined for their chemical composition, their nutritive value and their digestibility. The amino acid composition is not affected by the process of precipitation except that solvent precipitation seems to retain more methionine and less leucine than the heat process. Alfalfa and clover have similar amino acid patterns except that alfalfa has more cystine, aspartic acid and serine than clover. The lipids retained with the protein by the heat process contain much more linolenic and less palmitic, stearic, oleic and linoleic acids than those by the solvent process. Acetone retained more linoleic and linolenic acids and less stearic and palmitoleic acids than alcohol. The lipids of clover had more stearic and oleic acids than those of alfalfa. More mineral elements except Na and Fe and more carbohydrates were found in the solvent-precipitated concentrates than in the heat-coagula. Alfalfa protein concentrate was more digestible and had a higher P.E.R. value than clover protein concentrate. Both, however, were inferior to casein. Dispersibility in water was greater for solvent-precipitated than for heat-precipited concentrates.

Rôle de complémentarité des protéines solubles du lait pour un isolat de protéine de soja et pour la caséine en présence de lactose

Abstract The supplementary value of whey protein for a soybean protein isolate was determined in a diet containing 16.5% lactose. Two coprecipitates with different whey protein/casein ratios and containing 4% lactose were also compared on the basis of their nutritive value. The results were evaluated on the basis of growth curves, protein efficiency ratios (PER) and digestibility coeffecients of the protein fraction of the diets. When lactose made up 16.5% of the diet, growth was not affected but protein efficiency decreased.

Irradiation du Jus de Pomme I. Effets des rayons γ sur Ie taux de filtration et Ia viscosité1

Abstract Freshly extracted, apple juice was submitted to different doses of γ rays (75 to 600 Krads). Filtration rates were measured and it was observed that, by increasing the dose of irradiation, the filtration rate was increased. A minimum of 150 Krads appeared necessary to produce changes in filtration ability. Observations on the viscosity of irradiated juices are in the same order as those made on the filtration rates: as the dose increases, the viscosity decreases. However differences in viscosity do not explain alone differences in filtration rates. It has been observed that a gel is formed on the surface of the filter and irradiation decreases this formation.

Relevé et évolution de la mycoflore sur des fraises durant l’ entreposage frigorifique

Resume Parmi les neuf especes d’organismes fongiques qui ont ete isolees de la surface de fraises et identifiees, les trois suivantes dominaient nettement par la frequence de leur presence: Mucor sylvaticum, Penicillium sp et Botrytis cinerea . La methode d’evaluation de la contamination basee sur le simple comptage des fruits moisis a donne des resultats comparables a ceux qui sont obtenus par la methode plus elaboree et plus complexe d’Howard. L’entreposage a 0 ou 1 C de fraises enveloppees d’un film de resinite VF a permis une conservation d’au moins 20 jours: cinq jours de plus, environ, que la duree obtenue a l’air libre saturee de vapeur d’eau. Ces fraises a-demi-mures se sont conservees plus longtemps que les fraises mures.