الفهرس | Only 14 pages are availabe for public view |
Abstract Fermented dairy products have a positive health outlook over the past years . Frozen yoghurt has become a common product especially after the addition of some natural fruits and vegetables to produce a high quality FY and the acceptable chemical, functional and sensory qualities . Using of carrot puree solids, carrots with orange juice solids or persimmon pulp solids as a fat replacer, an alternative milk fat, a source of dietary fiber and natural antioxidants. Previous studies refer to the importance of adding such natural sources to food in general and dairy products in particular to increase their functional properties of these products. Therefore, this study aims to produce of functional frozen yoghurt with new and suitable flavour for Egyptian taste and provide many functional properties with high quality and reasonable price. Carrots, orange and persimmon were selected as means of replacing different percentages of fat in the FY to reach the best sensory, chemical and rheological properties. This is in addition to produce a product acquired functional properties and healthy benefits. The study is divided into three parts as follows: Part 1 Influence of addition carrot puree solids (CPS) to frozen yoghurt on some physical, rheological, bacteriological and organoleptic properties Five treatments were done as follows: 1- T1 : Full fat (4% fat) frozen yoghurt (FY) without CPS (control1 ). 2- T2 : Treatment with 3% fat FY with adding 1% CPS. 3- T3 : Treatment with 2% fat FY with adding 2% CPS. 4- T4 : Treatment with 1% fat FY with adding 3% CPS. Summary 152 5- T5 : Treatment with 1% fat FY without adding CPS (control2 ). The results obtained can be summarized as follows: 1- Specific gravity and weight per gallon of FY significantly (p≤0.05) higher for CPS treatments than full fat or low fat control (T 1 and T5 ) treatments. 2- The reduction in the freezing point degree increased significantly (p≤0.05) with the increase of CPS added ratios to FY treatments. 3- The apparent viscosity of CFY increased significantly (p≤0.05) in parallel with the added ratios of CPS. T4 treatment had higher apparent viscosity than other treatments. 4- The total viable LAB decreased significantly (p≤0.05) with the addition of CPS after aging compared with control treatments (T1 and T5 ). 5- Specific gravity and weight per gallon of CFY significantly (p≤0.05) increased with added CPS compared with control (T1 and T5 ) treatments. 6- Overrun % of CFY increased significantly (p≤0.05) in parallel the with added CPS compared with T5 treatment. T1 treatment had the highest overrun %. 7- The melting rate % of CFY made with addition of different ratios of CPS decreased significantly (p≤0.05) during 60 min compared with controls (T1 and T5 ) treatments. T4 treatment recorded a lowe st melting rate followed by T3 and then T 2 . 8- Color measurement: L* value: White colour, a*: Green and red colour and b*: Yellow and blue colour.. |