| Popis: |
Most set soybean yoghurts have the problem of poor taste and flavor, and the overall quality is not as good as that of fermented milk. In order to improve the quality of set soybean yoghurt and to improve the flavor of set soybean yoghurt, a plant oil with pleasant flavor was added in the preparation of set soybean yoghurt. The effects of the addition of olive oil and coconut oil on the physicochemical quality, sensory quality, and nutritional quality of set soybean yoghurt, as well as the effects of fermentation and in vitro digestion on the distribution of oil in set soybean yoghurt, were investigated. Three kinds of set soybean yoghurt without oil, with coconut oil, and with olive oil were prepared. The results of GC–MS analysis showed that the set soybean yoghurt without oil contained only two esters and one alcohol: delta-dodecalactone, 5-decanolide, and R-(−)-2-butanol. The set soybean yoghurt with olive oil was characterized by five volatile flavors: hexanoic acid, 2-nonanol, phenylacetaldehyde, 3-heptylacrolein, and acetylpyrazine. The set soybean yoghurt with coconut oil was characterized by nine volatile flavors: 5-hydroxyoctanoic acid lactone, ethyl caprylate, ethyl caprate, ethyl laurate, 2-tridecanone, dihydro-2-methyl-3(2H)-thiophenone, lauric acid, 1-octanol, and 2-decanol. Gas chromatographic analysis showed that the set soybean yoghurt without added oil contained seven free fatty acids. The set soybean yoghurt with olive oil contained 10 kinds of free fatty acids and was high in oleic acid. The set soybean yoghurt with coconut oil contains nine kinds of fatty acids and is rich in lauric acid. By laser confocal microscopy observation, the oil droplets in the three groups of set soybean yoghurt were aggregated after fermentation, and the oil droplets in the three groups of set soybean yoghurt were reduced after digestion. Research has proved that adding an appropriate amount of olive oil or coconut oil to set soybean yoghurt can improve the taste and the flavor, and that the addition of oil does not increase the digestive burden. |
