Chemical and sensory analysis of strawberry flavoured yogurt supplemented with an algae oil emulsion.

A yogurt mix (2 g fat and 17g solids/100 g) was supplemented with an algae oil emulsion to provide 500 mg omega-3 fatty acids per 272 g serving of yogurt white mass. The emulsion was added to the yogurt mix either before or after the homogenization step and prior to pasteurization. It was then flavoured with a strawberry fruit base and fermented and stored for up to three weeks. The oxidative deterioration of the products was determined by hydroperoxide measurements and by trained and consumer sensory evaluations. The hydroperoxide content of the supplemented yogurts increased over the storage treatment and was unaffected by the stage of addition. The trained panel could distinguish a stronger fishy flavour in both of the supplemented yogurts after 22 days storage, but the consumer panel rated both control and supplemented samples similarly, as 'moderately liked'.

Photooxidative Stability of Vitamin A Fortified 2% Lowfat Milk and Skim Milk.

Lowfat milk and skim milk were fortified with either oil- or aqueous-based carrier blends of vitamins A and D, in 1-gal poly-ethylene containers, and illuminated up to 72 h with 1080 1× (100 ft-c) at 5°C in a commercial display case. Vitamin A measurments and sensory analyses showed that vitamin A was more stable in 2% lowfat milk than in skim milk regardless of the carrier. The aqueous-based carrier provided more stability in lowfat milk while the oil-based carrier gave more stability in skim milk. Skim milk fortified with the aqueous-based vitamin A had 69% loss, while the unexposed control exhibited only 15% loss of the vitamin. Off-flavors were evident after 6 h in light-exposed 2% lowfat milk with the oil-based vitamin A, but the same milk with aqueous-based vitamin A did not exhibit off-flavors until after 12 h. Both 2% lowfat and skim milk samples exposed to light received similar lowered preference scores compared to nonexposed control samples. When both fortified and nonfortified 2% lowfat and skim milk samples were tasted after exposure to light, the flavor was not significantly different, but were in the unacceptable range.