Determination of quality characteristics of aronia (aronia melanocarpa) pulse dried with different drying methods and its use in buffalo yogurt

In this study, the aim was to develop a functional dairy product rich in bioactive compounds and beneficial to health by adding aronia fruit pulp powder obtained using different drying methods to buffalo yoghurt. Aronia pulp was dried using a solar collector (GK) dryer, a rotary tray dryer (DT), and an oven (ETV) at different temperatures and durations, and analyses of total phenolic content, phenolic content, total anthocyanin content, and antioxidant activity were conducted on these samples. Based on the analyses, the aronia pulp powder dried using the GK had the highest anthocyanin content (8.40 ± 0.37 mg CGE/g), total phenolic content (TFM) (40.54 ± 2.25 mg GAE/g), and antioxidant activity (DPPH) (73.05 ± 0.50 mM trolox/g) were added to buffalo milk at ratios of 1% (Sample A), 2% (Sample B), and 3% (Sample C). The pH, titration acidity (TA), lactic acid bacteria growth, L, a, b, chroma (c), and hue (h) of the functional yoghurt samples, were evaluated for product quality by monitoring bioactive component content, pH, titration acidity (TA), lactic acid bacteria growth, L, a, b, chroma (c) and hue (h) colour values, rheological properties (water-holding capacity, serum separation) and sensory characteristics throughout the storage period. With the progression of storage time, a statistically significant (p<0.05) decrease in pH values was observed in all samples. Although there were fluctuations in titratable acidity values in different samples, a generally stable trend was observed. With an increase in the amount of aronia pulp powder, an increase in syneresis and a decrease in water retention capacity were observed in yoghurt samples. In colour analyses, the highest L values were obtained in the K sample on all storage days, and L values decreased in parallel with the increase in aronia pomace powder content (K>A>B >C). An increase in a value and a decrease in b value were observed with the addition of aronia pomace. Anthocyanin content, TFM, and antioxidant capacity (DPPH) increased with the increasing ratio of pulp. The highest anthocyanin (136.35 ± 1.09 mg/kg), TFM (454.1 ± 59 mg GAE/kg), and DPPH (1.22 ± 0.14 mMol troloks/g) values were observed in the C sample. The amounts of phenolic compounds such as gallic acid, 3,4-dihydroxybenzoic acid, catechin, vanillic acid, epicatechin, ferulic acid, t-resveratrol, rutin trihydrate, and quercetin were analysed in the yoghurt samples. In the sensory evaluation, the control sample (K) received the highest score in all sensory evaluations on day 1. The sample with 3% aronia pomace powder added (C) received a visual score very close to that of the control group on day 1 (8.00 ± 0.27). The aronia pomace powder addition did not significantly affect the consistency of the yoghurt. In the aronia pomace powder added samples, the initial taste scores were generally lower than those of the control group. A decrease in mouthfeel was observed with increasing aronia pomace powder content. In terms of overall acceptability, samples A and B approached the control sample (7.63 ± 0.46) with a score of 7.13 ± 0.30 on day 10. In conclusion, this study demonstrated that aronia pomace powder can be evaluated as a functional food ingredient in buffalo yogurt. Keywords: Aronia Pulp, Buffalo Yogurt, Waste Utilization, Phenolic, HPLC