Canadian Institute of Food Technology Journal最新文献

A method is outlined for the determination of organic acids by precipitation as lead salts. The results of this method, as applied to pigmented and decolorized fruit juices, are compared to titratable acidity and organic acid analysis obtained via ion exchange column chromatography on the same juices. The results indicate that the values obtained by lead precipitation of organic acids, corrected for precipitation due to the presence of orthophosphate, provides a far more accurate picture for organic acids content than titratable acidity alone and may provide a routine procedure for estimation of total organic acids in fruit and vegetable products.

Malic, oxalic and citric acids are the only non-volatile organic acids present in ripening Saskatoon berries (Alnifolia sp.) in measurable concentrations. The levels of these acids, as well as the levels of glucose, fructose and sucrose are reported for three varieties of Saskatoons presently being cultivated at the Canada Department of Agriculture Research Station at Beaver-lodge, Alberta. Results indicate that the organic acids content of Saskatoons is comparable to that of apples, and that the fructose levels in the berries may decrease fairly rapidly after ripening.

A survey started in May 1967 to obtain information on the composition of Alberta milk was carried through to the end of April 1969. It provided one year's results on the composition of monthly samples from six herds (3 Holstein, 2 Guernsey and 1 Ayrshire), and two years' results on monthly bulk samples from six areas in the Province. The following averages were observed for percentages of protein, fat and solids-not fat, and for freezing point (-°C): Holstein: 3.249, 3.641, 8.606, 0.5398; Ayrshire: 3.396, 3.841, 8.839, 0.5369; Guernsey: 3.696, 4.890, 9.244, 0.5412; bulk milk samples (overall); 3.229, 3.585, 8.532, 0.5388.

Variations by centre and by season are reported for the bulk milk samples and, where possible, comparisons are made with results from recent Manitoba and Ontario studies. Correlation coefficients and regression equations for constituents in the bulk milk samples were as follows: protein and fat 0.24, Y = + 0.17X; solids-not-fat and protein 0.19, Y = 7.96  + 0.18X; solids-not-fat and fat 0.435, Y = 7.41 + 0.31X.

The design and operation of Canada's first commercial jacketed vegetable storage is described, with an outline of the basic principles involved. The room is of economical wood frame construction with fiberglass insulation. The jacket feature increased construction cost about 15%. The results obtained in the first year of operation were considered to be excellent because of the high quality maintained in the stored produce (carrots and cabbage). Decay was also lower than in non-jacketed rooms For the second year, measures taken to improve internal air circulation (modification of pallet boxes and stacking arrangement, and installation of an economical fan-duct system) were very effective, with further improvement in storage conditions. The high quality and extended storage life of the produce resulted in a marketing advantage since it was possible to sell on the basis of market demand rather than on the basis of limited storage life.

The nitrate contents of a number of canned foods, baby foods frozen foods and vegetables were determined. Spinach, beets'and several fruits were found to generally have the highest nitrate content. Nitrate was partially transferred to the liquid nortion of foods consisting of a solid immersed in liquid and was also transferred to blanching water. The rate of transfer of nitrate from solid to liquid varied for different foods and different plant parts. Nitrate was not lost during cooking but nitrate reductase activity was quickly destroyed by cooking. The use of nitrate fertilizers on soil markedly increased nitrate content of plants growing in that soil.