Ines Panjkota Krbavčić

Phenolic Content, Antioxidant Capacity and Quality of Chokeberry (Aronia melanocarpa) Products

In this study, the influence of lactic acid fermentation on the quality of tomato powder was evaluated. The effect of adding fermented tomato powder to ready-to-cook minced pork meat to improve its nutritional value and sensory characteristics was also analysed. The cell growth of Lactobacillus sakei (7.53 log CFU/g) was more intense in the medium containing tomato powder, compared to the growth of Pediococcus pentosaceus (6.35 log CFU/g) during 24 h of fermentation; however, higher acidity (pH=4.1) was observed in the tomato powder samples fermented with Pediococcus pentosaceus. The spontaneous fermentation of tomato powder reduced cell growth by 38% and pH values slightly increased to 4.17, compared to the fermentation with pure LAB. The lactofermentation of tomato powder increased the average β-carotene and lycopene mass fractions by 43.9 and 50.2%, respectively, compared with the nonfermented samples. Lycopene and β-carotene contents in the ready-to-cook minced pork meat were proportional to the added tomato powder (10 and 30%). After cooking, β-carotene and lycopene contents decreased, on average, by 24.2 and 41.2%, respectively. The highest loss (up to 49.2%) of carotenoids was found in samples with 30% nonfermented tomato powder. Tomato powder fermented with 10% Lactobacillus sakei KTU05-6 can be recommended as both a colouring agent and a source of lycopene in the preparation of ready-to-cook minced pork meat.Chokeberries (Aronia melanocarpa) are rarely used in diet in Croatia but they have high content of polyphenolic compounds and one of the highest in vitro antioxidant activities among fruits. The aim of this study is to compare the quality, phenolic content and antioxidant capacity of different chokeberry products (juices, powders, fruit tea, capsules and dried berries). It can be expected that processing influences antioxidant activity and phenolic content of final products reaching consumers. Characterisation of phenolic compounds was carried out by using spectroscopic methods (Folin-Ciocalteu and pH differential methods). Antioxidant activity of chokeberry products was determined using 2,2-diphenyl-2-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) methods. The results show that the investigated products contain high amount of phenols (3002 to 6639 mg per L and 1494 to 5292 mg per 100 g of dry matter) and lower amount of total anthocyanins (150 to 1228 mg per L and 141 to 2468 mg per 100 g of dry matter). The examined juices and other chokeberry products possess high antioxidant capacity (12.09 to 40.19 mmol per L or 58.49 to 191.31 mmol per 100 g of dry matter, respectively) and reducing power (38.71 to 79.86 mmol per L or 13.50 to 68.60 mmol per 100 g of dry matter, respectively). On the basis of phenolic content and antioxidant activity, capsules and powders stand out among other products. The study indicates that there are significant differences (p<0.05) in the quality, phenolic content and antioxidant capacity among examined products.

Effects of Weather Conditions on Phenolic Content and Antioxidant Capacity in Juice of Chokeberries (Aronia melanocarpa L.)

Abstract Chokeberries are a subject of numerous studies due to a high phenolic compound content, antioxidant properties and potential positive influence on the health. Effects of weather conditions on fruit quality attributes, phenolic compounds and antioxidant capacity of chokeberry (Aronia melanocarpa) juice over three consecutive years were investigated. Total phenolic content and total flavonoids range were from 8834 to 11093 mg/L and from 6993 to 9710 mg/L, respectively. High variations and discrepancy during different growing seasons are due to the different air temperature, sunlight and rainfall rate. The highest concentrations of anthocyanins and phenolics were observed in fruits harvested in 2012, which is most likely due to the favorable weather conditions (temperature and bright sunshine hours). All chokeberry juices possess high antioxidant activity (12.9–14.6 mmol/L; 128–167 mmol/L). Strong correlation implies that flavonoids and non-flavonoids were the major contributors to the antioxidant capacity. This study indicates that although the examined properties vary considerably through the growing seasons (p≤0.05), chokeberry juices can serve as a good source of bioactive phytochemicals in a human diet.

The impact of education and cooking methods on serum phosphate levels in patients on hemodialysis: 1‐year study

Introduction: Control of serum phosphate is important for patients on hemodialysis. The aim of the study was to determine if education based on phosphorus‐reducing techniques in food preparation and thermal processing, and accordingly prepared and applied diets, will lead to better outcomes than a standard education program to improve phosphate control in patients on hemodialysis.