| Popis: |
The aim of this research was to assess the seasonal change in milk fat composition and determine the effects that these changes had on properties of chocolate, such as snap, hardness, shelf life, gloss, temperability and sensory attributes. Milk samples from two lactation seasons were collected. The fat was extracted and analysed by gas-liquid chromatography for the fatty acid and triglyceride composition. These samples were also analysed by nuclear magnetic resonance to determine the solid fat content at various temperatures. The relative proportions of the fatty acids and triglycerides in the milk fat samples were found to vary throughout the lactation period, showing distinct seasonal trends. The variation in the relative proportions of the fatty acids in the milk fat influenced the relative proportions of specific triglycerides in the milk fat. The solid fat content (SFC) of the milk fat also varied throughout the lactation period with the lowest SFC, or the softest milk fat, being present in spring and the highest SFC, or the hardest milk fat, being present in summer. The SFC was influenced by the fatty acid and triglyceride composition of the milk fat. The seasonal trends in the relative proportions of the fatty acids and the triglycerides and the percentage of solid fat in the milk fat were the same for both lactation seasons assessed. |
