4. Conclusion
This study demonstrated that Pinot Noir wine grape pomace
may be utilized as an alternative source of antioxidant dietary fibre
to fortify yogurt and salad dressing for not only increasing dietary
fibre and total phenolic content but also delaying lipid oxidation of
samples during refrigeration storage. Although products fortified
with the pomace extracts (liquid and freeze dried) obtained the
most similar physicochemical properties to the control (no pomace
added), those fortified with dried whole pomace powders (WP) had
higher dietary fibre content. Unfortunately, total phenolic content
(TPC) and DPPH radical scavenging activity (RSA) of fortified samples
decreased during storage, in which more reduction was observed
in yogurt than that in salad dressings, probably due to the
interactions between proteins in yogurt and phenolic compounds
in pomace. Therefore, it is necessary to further investigate the
mechanisms and methods of retention of TPC and RSA in the products
in the future studies by using chromatographic techniques to
profile the change of pheonolic compounds. Based on the balance
in DF and TPC contents, RSA value, physicochemical qualities and
consumer acceptance, the best received products were 1% (w/w)
WP fortified yogurt, 0.5% (w/w) WP fortified Italian dressing, and
1% (w/w) WP fortified Thousand Island dressing.