Aroma-active secondary oxidation products of butter

Butter contains vitamins, minerals and unsaturated lipids, such as polyunsaturated fatty acids (PUFA) and conjugated linoleic acids (CLAs). However the oxidative stability and consequently the shelf-life of milk products are inversely correlated with their PUFA and CLA content. The objective of this study is the evaluation of the oxidative stability and sensory quality of PUFA/CLA-enriched butter versus conventional butter, with both types of butter being produced at ALP. For this purpose, new chemical and sensory-based methods will be developed, as well holistic complementary methods. This paper focuses on a preliminary study achieved using conventional butter, subjected to a long storage and to oxygen and light exposure, to develop a gas chromatography olfactometry (GC-O) method able to detect the aroma-active compounds originated from oxidation. This will be one of the methods used for the evaluation of the oxidative stability of PUFA/CLA-enriched butter

Organic Food Processing

This session deals with principles and future concepts including the further development of Annex VI of EU regulation 2092/91

Influence of a dry fractionation of butterfat on the content of fatty acids including conjugated linoleic acids

There is a growing demand among consumers for food products with natural nutritional-physiological advantages over comparable conventional products. As part of an EU project, a process using dry fractionation is evaluated that enables the targeted lowinput enrichment of conjugated linoleic acids (CLA) in milk fat. Furthermore, the distribution of CLA isomers in the fat fractions was analysed. In the olein fraction for highland butter a CLA enrichment of 15.3% was obtained. The yield of the CLA rich olein fraction was 44.5% of the total amount of olein and stearin. There were significant increases during the first fractionation step of highland butter for the concentration of the CLA isomer cis-9, trans-11 (P £ 0.05) and during the second fractionation step for the concentration of CLA isomers cis-9, trans-11; trans-11, cis-13 (P £ 0.05) and trans-7, cis- 9 (P £ 0.01). Experiments carried out demonstrate that the selected physical separation process enables CLA enrichment but the increase is too minor to achieve any decisive positive impact on human health and therefore too costly as an industrial CLA enrichment process

Conjugated linoleic acid isomer concentrations in milk from high- and low-input management dairy systems

BACKGROUND: Different conjugated linoleic acid (CLA) isomers are known to have contrasting physiology or health effects and there is growing evidence that the profile of natural isomers in milk is influenced by the production system. This survey is the first to compare feeding regimes and concentrations of 14 CLA isomers inmilk from three production systems in the UK. RESULTS: Total CLA and seven isomers (including C18 : 2 c9t11 which comprised >80% of total) were significantly higher in milk from both organically certified and non certified low input (LI) systems compared with milk from conventional high input farms. Sampling date also affected concentrations of total CLA and nine isomers; being lowest in March and highest in August. Seasonal differences were greater in milk from LI herds, thought to be due to changes in herbage and/or stage of lactation. Multivariate analysis showed a strong positive relationship between several CLA isomers and increasing levels of fresh forage in the diet. CONCLUSIONS: These results add to the evidence on how management adjustment may improve the profile of CLA isomers in milk fat, although animal or human intervention studies are required to identify the effects of consuming milk with different CLA levels and isomer profiles on human health. (c) 2009 Society of Chemical Industr

The effects of dairy management and processing on quality characteristics of milk and dairy products

Studies within the QLIF project reviewed in this article suggest that organic or low-input management is more likely to result in milk with fatty acid profiles that are higher in α-linolenic acid and/or beneficial isomers of conjugated linoleic acid and antioxidants with up to a 2.5-fold increase in some cases, relative to milk from conventional production. These advantages are preserved during processing, resulting in elevated contents or concentrations of these constituents in processed dairy products of organic or low input origin. Much of the literature suggests that these benefits are very likely to be a result of a greater reliance on forages in the dairy diets (especially grazed grass). Since the adoption of alternative breeds or crosses is often an integral part sustaining these low-input systems, it is not possible to rule out an interaction with genotype in these monitored herds. The results suggest that milk fat composition with respect to human health can be optimized by exploiting grazing in the diet of dairy cows. However, in many European regions this may not be possible due to extremes in temperature, soil moisture levels or both. In such cases milk quality can be maintained by the inclusion of oil seeds in the dairy diets