Flavour and vitamin stability in pasteurized milk in polyethylene‐coated cartons and in polyethylene bottles

Abstract

Commercially pasteurized, non‐homogenized full cream milk in 2‐pt white polyethylene (PE)‐coated cartons overprinted with blue, and in 4‐pt PE bottles was stored for 4 d in the dark or under white fluorescent light of 4000 1x, at a temperature of 7°C. The flavour of milks kept in the dark remained good, but exposure to light resulted in early off‐flavour development: cartoned milk was disliked by a flavour panel after about 17.5 h exposure and milk in the PE bottles after 9 h. Vitamins A and B2 were stable in the milk during 4 d storage in the dark in both bottles and cartons, and in cartons exposed to light. In the bottled milks, light‐induced losses of these vitamins after 4 d were, respectively, 15% and 35%. but there was little or no loss before the development of light‐induced flavour. Loss of total vitamin C by day 4 was about 50% in the dark, irrespective of container. In the cartons exposed to light, 66% of the vitamin C was lost, while virtually none remained in the exposed, bottled milk. There was also a markedly greater loss of vitamin C in the bottled milk than in the cartoned milk at the time the flavour became unacceptable. The dissolved O2 concentration dropped considerably in the bottled milk exposed to light, but only marginally in the cartons. There were small increases in dissolved O2 in the dark in both types of container.

Changes in flavour volatiles of whole pasteurized milk as affected by packaging material and storage time

“…Problems with all-plastic containers used in the studies cited above included light transmission and oxygen permeability. It should be noted, however, that oxidative reactions (auto-oxidation) have been reported to take place in milk packaged even in coated paperboard cartons which were found to be more or less impermeable to oxygen (Rysstad, Ebbesey, & Eggestad, 1998;Schro¨der et al, 1985). More recently, polyethylene perephthalate (PET) and coextruded high-density polyethylene (HDPE) bottles have been used for fresh milk packaging (Bakish & Hatfield, 1997;Cladman, Scheffer, Goodrich, & Griffiths, 1998; van Aardt, Duncan, Marcy, Long, & Hackney, 2001).…”

“…Apart from traditional glass bottles and coated paperboard cartons, all-plastic containers have been used for pasteurized milk packaging (Defosse, 2000;Schro¨der, Scott, Bland, & Bishop, 1985). Problems with all-plastic containers used in the studies cited above included light transmission and oxygen permeability.…”

Vitamin Fortification of Fluid Milk

“…The human eye can typically respond to wavelengths from 390 to 700 nm (Starr ). Light exposure at wavelengths below 500 nm causes the destruction of light‐sensitive vitamins such as riboflavin, vitamin A, and vitamin C, induces chemical reactions that affect milk proteins and lipids, and results in the development of unpleasant flavors in fluid milk (Fanelli and others ; Sattar and others ; Schroder and others ). Dairy products are very sensitive to light oxidation because of the presence of riboflavin (vitamin B 2 ).…”

Advanced Dairy Chemistry Volume 3

“…Many studies have been performed to define the extent of this breakdown and to examine how different types of bottles and packaging materials may protect the vitamin (Hansen et al, 1975;Singh et al, 1975;Maniere and Dimick, 1976;Goussalt et al, 1978;Bradley, 1980;Scott et al 1984b;Schroeder et a/., 1985;Gaylord et al, 1986;Secomska and Nadolna, 1987;Tagliaferri, 1989). Present evidence shows that the use of packaging material that offers little or no protection against light is detrimental to the riboflavin content, whether the illumination takes place in sunlight or in the retail store.…”