Effect of naked oats in the dairy cow’s diet on the oxidative stability of the milk fat

Abstract

Oxidative stability of milk fats from cows offered naked oats‐ and barley‐based diets were compared in shelf‐life tests using the Schaal Oven Test at 63°C, and determination of peroxide and thiobarbituric acid values. Milk fat from cows offered the diet containing naked oats, although containing a higher proportion of monounsaturated fatty acids, had a significantly longer oxidation induction period (13 days) than milk fat from cows offered the control (barley‐based) diet (9 days). However, sensory testing of the milk fats indicated that a perceptible odour difference was apparent between stored (63°C) and unstored milk fats after 3 days of storage irrespective of the diet fed. It is possible that the odours perceived may have originated from the cows' diets or from hydrolytic rancidity reactions. The difficulties of relating chemical and sensory testing of the oxidative deterioration of milk fat or butter are underlined. © 1998 SCI.

Traditional Tunisian butter: Physicochemical and microbial characteristics and storage stability of the oil fraction

“…Churning is the most important step for butter-making, during which the oil-in-water emulsion is broken, leading to aqueous phase separation and formation of water-in-oil emulsion (Rousseau, 2000). The quality of stored butter is governed by such factors as cream ripening, the manufacturing process, good hygienic practice (GHP) when processing and handling, the storage temperature, and type of animal feeding (Fearon, Mayne, & Charlton, 1998). Despite the application of preventive measures (refrigeration and GHP) during its production and its distribution, TTB has a limited shelf-life.…”

“…Therefore, the determination of the peroxide value can be used as an oxidative index for the early stage of lipid oxidation (Ramadan & Mö rsel, 2004). The initial stage of slow oxidation (the induction period) can be measured as the time required to reach an endpoint of oxidation corresponding either to a level of detectable rancidity (a defined peroxide value) or to a sudden change in oxidation rate (Fearon et al, 1998). The peroxide values obtained for TTBO proceeded at a lower rate initially.…”

Dietary sources of unsaturated fatty acids for animals and their transfer into meat, milk and eggs: A review

“…However, Fearon et al (1998Fearon et al ( , 2004 reported that substantial increases in milk fat MUFA (+21% and +35% from offering naked oats plus grass silage or whole rapeseed at grass, respectively) had little or no adverse effects on butter oil oxidative stability (Schaal Oven test at 63°C). Gonzalez et al (2003) also reported no difference in peroxide or acid values for ice cream prepared from control, high-oleic milk (+23%) or high-linoleic milk (+113%) over two months storage.…”

Effect of feeding oilseed supplements to dairy cows on ruminal and milk fatty acid composition

“…The higher C18:1n-9 proportions and lower C16:0 proportions of the milk fats from the cows offered the high-lipid diets resulted in lower solid fat contents at temperatures of 0±35°C and hence softer butter fats. 24 The signi®cant difference in the solid fat content of the milk fat from the rapeseed-based diets may be the result of the signi®cantly higher C18:2n-6 fatty acid content in the milk fat from the cows which were offered the ground rapeseed-based diet.…”