Infants rely on their innate immune systems to protect them from infection. Human milk (HM) contains fatty acids (FAs) and monoacylglycerols that are known to exhibit antiviral and antibacterial properties in vitro. The specific fat content of HM may potentially affect the efficacy of this antimicrobial activity. This preliminary study investigates whether the proportions of FA in HM change in response to infections, leading to cold-like symptoms in the mother or infant. Milk samples were obtained from mothers (n = 26) when they and their infants were healthy, and when mother, infant, or both suffered cold-like symptoms. The milk was hydrolysed and FA proportions were measured using gas chromatography. Fifteen FAs were recorded, of which eight were detected in sufficient quantities for statistical analysis. The proportions of capric (C10:0) and lauric acids (C12:0) in HM were significantly lower, and palmitic acid (C16:0) was higher when mothers and infants were ill compared to healthy samples. Palmitoleic (C16:1, n-7) and stearic acid (C18:0) proportions were higher in HM when the infant was unwell, but were not related to maternal health. Whilst the differences detected were small (less than 0.5%), the effects may be additive and potentially have a protective function. The value of further studies is certainly indicated.

Variations in the crystallization behavior of fats have important consequences for the processing of fatty foods. This paper is concerned with the changes in the crystallization of coconut oil due to refining, and the effects of diacylglycerols, free fatty acids and phospholipids on oil crystallization.The changes in coconut oil crystallization due to changes in oil composition have been studied by pulsed nuclear magnetic resonance spectroscopy. Bleaching or neutralization of crude coconut oil caused a dramatic reduction in the induction time before the onset of detectable crystallization at 15°C. The addition of oleic and lauric acid caused a large increase in the induction time of refined coconut oil whereas palmitic acid had a smaller effect. However, the changes in coconut oil crystallization during refining are not completely explained by the removal of free fatty acids. Dilaurin retarded the nucleation of coconut oil whereas diolein did not have any significant effect. Phosphatidylcholine also retarded the nucleation of coconut oil at 15°C, but this effect is not significant in practice for coconut oil because of the low levels of phospholipids present in the crude oil.

The effect of various processing procedures on the composition and oxidative stability of coconut oil has been studied. The crude oil is relatively stable but major reductions in oxidative stability occur during the bleaching of oil degummed with phosphoric acid; during alkali refining; during the deodorization of oil degummed with citric acid and bleached; and during the deodorization of oil prc~ cessed with a combined phosphoric acid degumming and bleaching operation. The reasons for the loss of oxidative stability during processing are discussed with reference to changes in the composition of the oil. Residual traces of citric acid or phosphoric acid play an important role in stabilizing processed oils. The tocopherol content is also important, although no additional stabilization of the oil occurs on adding levels of tocopherol above those present naturally in the crude oil. A combined phosphoric acid degumming and bleaching process leads to smaller losses of tocopherols than sequential treatments.Crude edible oils may be processed by various procedures in order to obtain an oil of optimum quality in high yield.Degumming, alkali refining, bleaching and deodorizing have traditionally been used for many oils with wide variations in processing conditions and procedures, including the replacement of alkali refining by physical refining.It is known that refining has a strong effect on the oxidative stability of oils. Jung et al. (1) found that crude soybean oil became less stable during processing with the order of stability being crude > deodorized > degummed > alkali refined > bleached oil. Other studies have also shown that crude oil is more stable than processed oil {2,3}. The stability of the oil is dependent on the presence of minor components including tocopherols, metal ions and phospholipids, which are partly removed during processing. Tocopherols, which act as natural antioxidants, are lost at-each stage of processing with total losses of 31-47% being reported during the processing of soybean oil (1,4} and 94% during the processing of coconut oil {5). Phospholipids and metal ions are mainly removed during degumming (6} with further losses during subsequent steps {1). Bleaching removes pigments including chlorophyll and carotenoids, but the hydroperoxide level may also be reduced at this stage (7} with residual hydroperoxides decomposing during deodorization {1}.This study was concerned with a detailed investigation of the effect of variations in processing conditions on the composition and oxidative stability of crude coconut oil. EXPERIMENTAL PROCEDURESCrude coconut oil supplied by Van den Berghs & Jurgens, Purfleet, U.K., was processed in the laboratory on a scale of 0.5-1 kg. Fuller's earth for bleaching was purchased from BDH Chemicals Ltd, Poole, U.K. Degumming and bleaching operations were performed at 80°C under nitrogen and vacuum. Alkali refining of selected samples was performed at 70 ° by addition of sodium hydroxide solution (0.8M, 10% excess of that required to neutralize the free fatty acid...

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