Properties of Low Fat Bio-frozen Yoghurt Fortified with Extract and Powder of Pomegranate Peel (Punicaganatum L.)

Abstract

The present study aimed at using Pomegranate peel powder and extract (PPPE) (Punica ganatum L.) as a source of dietary fiber, natural colorant, prebiotic, polyphenols, and antioxidant activity in developing low fat frozen yoghurt. Pomegranate peel has been added in form of powder (added to yoghurt at at a rate of 1.5%) and extract (added at a rate of 0, 25, 50, 75, and 100% as a substitute of water used in preparing the frozen yoghurts that given codes of T1, T2, T3, and T4).Also, control frozen yoghurt sample was prepared without fat replacer (simplesse) as compared to other treatments. The results of frozen yoghurt revealed that the conversion of yoghurt into frozen mix caused an increments in acidity, viscosity, total phenolic content, total flavonoids content, and antioxidant activity values. Moreover, the viable count of lactic acid bacteria strains increased in frozen yoghurt mix. While the pH value, specific gravity (sp.gr.) and freezing point have been decreased by adding PPPE. Also, adding PPPE along with the fat replacer (simplesse) led to calorie reduction. Additionally, adding PPPE into traditional frozen yoghurt or bio-frozen yoghurt increased mineral content (Fe, Zn, P, and K). The freezing and hardening processes decreased the viable counts of LAB strains keeping its therabeutic level (106/g). Thus, T5 sample had the highest viable counts over storage time. The final frozen yoghurt was characterized with higher overrun, stronger melting resistance and the highest value of hardness as the PPPE were replaced and when it was made using ordinary yoghurt versus the bio-yoghurt. The quality of all sensory criteria of body and texture, flavour as well as overall quality of the PPPE-replaced frozen yoghurt was evidently better than that of the control, which was made with fat replacement. Scores ofsensory attributes increased with adding PPPE up to 100%.