Physicochemical, Microbiological Quality and Organoleptic Properties of Yoghurt Supplemented with Linseed Oil

Ismail, H. A.; Elgaml, N. B.; Tammam, A. A.

doi:10.21608/jfds.2016.46007

Physicochemical, Microbiological Quality and Organoleptic Properties of Yoghurt Supplemented with Linseed Oil

Document Type : Original Article

Authors

¹ Dairy Science Department, Faculty of Agriculture New Valley, Assiut University, Egypt.

² Animal Pro .Res. Institute, Agric. Res. Center, Ministry of Agric., Egypt.

³ Dairy Science Department, Faculty of Agriculture, Assiut University, Egypt.

10.21608/jfds.2016.46007

Abstract

Linseed oil is derived from the seeds of flaxseed (Linum usitatissimum L.), a plant widely cultivated for fiber or oil for industrial use. The aim of this study was to investigate the influence of milk supplementation with flaxseed oil with different percentage I.E., 0.0, 0.5, 1.0, 1.5 and 2.0 on the physico-chemical, microbiological and organoleptic characteristics of yoghurt during storage at 6⁰C for 14 days. The obtained results showed that total solids, acidity, fat, ash and total volatile fatty acids (TVFA) of yoghurt manufactured from milk supplemented with linseed oil were higher than that of control until day 14^th. There were marked variations in the fat content and TVFA value of the products. Yoghurt supplemented with 2% linseed oil exhibited lower pH value compared with other treatments. However, yoghurt supplemented with linseed oil showed gradual increase in total bacterial count and yeast & mould apparent on the 7^th day of storage while all samples showed a gradual decrease on 14^the day. Yoghurt samples supplemented with different percentage of linseed oil had higher in curd tension and whey syneresis compared with control. Results of the present study indicated direct relationship between all percentage of linseed oil and quality with higher levels of linseed oil. Results of the sensory evaluation revealed that flavour, consistency and appearance was significantly affected (p<0.05) on yoghurt samples. The colour of yoghurt was changed towards yellowness with the increase in the percentage of added linseed oil. Yoghurt containing linseed oil had slightly significant (P<0.05) decreased the acceptance level of aroma and texture of yoghurt. It could be concluded that the supplementing milk with linseed oil at percentage 1.0% was the most acceptable.

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