STUDY EFFECTS OF QUINCE SEED MUCILAGE AND GUAR GUM ON THE SENSORY CHARACTERISTICS AND THE VOLATILE COMPOUND PROFILE OF DOOGH BY GAS CHROMATOGRAPHY/ NANO-SIZED POLYPYRROLE FIBER

Abstract

Doogh as an acidified milk drink is produced by adding salt and water into yoghurt. In the present work the effects of some additives like; Quince seed mucilage (Qm) and guar gum (Gg) on the sensory properties of Doogh (odour, colour and overall acceptability) and its relation with the total peak area and total peak height of volatile compounds of doogh in gas chromatography (GC) were studied. Extraction of volatile compounds of doogh was done with polypyrrole fiber from a head space of doogh sample as head-space solid phase micro extraction method (HS-SPME). Polypyrrole (PPy) was chemically-deposited on the polyester fiber surface. The Electron Microscopy (SEM) technique showed that PPy particles are in the range of 50-150 nm and seed shape. Central composite design (CCD) and response surface methods were applied to design the experiments and find out the interaction among different factors and correlations among sensory properties and GC parameters (total peak area and total peak height) of compounds in doogh. The results showed that there is a positive relation between sensory properties and GC parameters of doogh and presented methods can be used for quality control of dairy products.