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The purpose of this study was to determine the possibility of using chokeberry powder as a supplement in apple juice to increase the nutritional value of the final product with the aim of developing a new functional food product. Also, to determine the influence of ultrasound assisted extraction on the bioactive compounds content, nutritional composition and antioxidant potential of apple juice with added chokeberry powder. The juice samples with added chokeberry powder had higher antioxidant capacity, irrespective of the extraction technique used. Apple juice samples with added chokeberry powder treated with high intensity ultrasound had significantly higher content of all analyzed bioactive compounds. The application of high intensity ultrasound significantly reduced the extraction time of the plant material. A positive correlation between vitamin C content, total phenols, flavonoids and anthocyanins content and antioxidant capacity was determined in juice samples with added chokeberry powder treated with high intensity ultrasound.

A b s t r a c t. The aim of this study was to investigate the influence of conventional and ultrasound-assisted extraction (frequency, time, temperature) on the content of bioactive compounds as well as on the antioxidant activity of aqueous extracts from fresh lemon balm and peppermint leaves. Total phenols, flavonoids, non-flavonoids, total chlorophylls, total carotenoids, and radical scavenging capacity were determined. Moreover, the relationship between bioactive compounds and antioxidant capacity was studied by linear regression. A significant increase in all studied bioactive compounds during ultrasonic extraction for 5 to 20 min was found. With the classical extraction method, the highest amounts of total phenols, flavonoids, and antioxidant activity were determined, and the maximum amounts of total chlorophylls and carotenoids were determined during 20 min ultrasonic extraction. The correlation analysis revealed a strong, positive relationship between antioxidant activity and total phenolic compounds.

Parsley highlights among other vegetables for high vitamin C content. It also contains minerals, essential oils, pigments, polyphenols and other compounds from the group of biologically active compounds characterized by high antioxidant activity. Parsley is cultivated and consumed for its leaves and roots with the three most common types: Petroselinum crispum ssp. tuberosum (turnip-rooted) and Petroselinum crispum ssp. crispum (curly-leaf), Petroselinum crispum ssp. neapolitanum (plain-leaf). The aim of this research was to determine the chemical differences and content of bioactive compounds in 6 parsley cultivars: 'Arat', 'Eagle', 'Halblange', 'Rialto', 'Mooskrause' and 'Petra'. Also, to determine the differences in nutritional composition between different parsley plant parts: leaf, stem and root. The highest vitamin C content in leaves (162.09 mg/100 g FW) was determined in cv. 'Rialto'. Root cultivars of Petroselinum crispum ssp. tuberosum (cv. 'Halblange') had higher vitamin C content. The highest total phenol content (425.76 mg GAE/100 g FW) was determined in leaves of cv. 'Arat'. The highest total chlorophyll content was determined in leaves in cv. 'Mooskrause', while the lowest in cv. 'Arat'. Average total chlorophyll content values in leaves of Petroselinum crispum ssp. neapolitanum and Petroselinum crispum ssp. crispum cultivars (0.69 mg/g) not differ from the average total chlorophyll content values of Petroselinum crispum ssp. tuberosum cultivars (0.69 mg/g). All parsley cultivars show high antioxidant capacity due to significant amounts of bioactive compounds such as chlorophylls, carotenoids, phenols, flavonoids, non-flavonoids and vitamin C.

The aim of this study was to compare physical and mechanical characteristics of Hisex hen eggs collected from three different housing systems: enriched cage housing, aviary housing, and free-range systems. The following physical and mechanical characteristics if eggs were compared: dimensions, surface area, volume, sphericity, shape index, shell thickness, weight, composition, yolk to albumen ratio, rupture force, specific deformation, absorbed energy, and firmness. The largest and heaviest eggs were collected from cage housing, followed by eggs from free-range systems and aviary housing. According to shape index, eggs from aviary housing can be described as round, while eggs from cage housing and free-range systems can be characterised as normal or standard. Eggs from free-range laying hens had the highest yolk percentage and yolk to albumen ratio (26.2% and 0.427). In comparison to eggs from aviary housing and free-range systems, eggs from enriched cage housing had the thickest shells and the highest shell strength, and required the highest force to rupture those eggs. The average force required to rupture Hisex Brown hen eggs from cage housing in all three axes was 44.14 N, which was 12.1% higher than the average force required to rupture eggs from a free-range system (39.37 N) and 17.1% higher than the average force required to rupture eggs from aviary housing (37.68 N). The highest forces required to rupture eggs from all three housing systems were determined on loading along the X-front axis and the lowest forces were determined along the Z-axis. The results obtained in this study can be useful to producers when selecting hen housing systems in order to reduce egg damage during storage and transport.

During the harvest season of two consecutive years, five strawberry cultivars ('Arosa', 'Elsanta', 'Marmolada', 'Miss' and 'Raurica'), grown in the continental part of the Republic of Croatia, were examined. Strawberry fruits quality was evaluated by individual phenol compounds, individual anthocyanins and fruit color. Fruits were harvested in three different periods. Analyzed strawberry cultivars show very good average values of the studied phenolic acids and flavonoids with predominant caffeic acid and epicatechin content in all researched strawberry cultivars. Considering the content of individual anthocyanins, pelargonidin 3-glucoside is predominant in strawberry extract followed by cyanidin-3-glucoside and pelargonidin 3-rutinoside. The correlation between individual anthocyanin content and chromaticity parameters was detected in all strawberry cultivars, additionally correlation coefficients and statistical significance were much lower. The results show a positive association between cultivar and harvest time on strawberry pulp color, with each of the color variables, a, b, a/b ratio, C, L and h° values.

The aim was to determine the differences in nutritional quality between chokeberry juices sweetened with sucrose and green stevia powder. The quality of chokeberry juices during refrigerated storage was studied. Chokeberry juices with added green stevia powder had the higher content of analyzed bioactive compounds in comparison with juice samples sweetened with sucrose; vitamin C content increased up to two times, total phenol content up to 6% and antioxidant capacity for 3%. The content of studied bioactive compounds and antioxidant capacity during storage in period of 30 and 60 days was significantly reduced with the exception of steviol glycosides which content was not significantly reduced during the storage period. Practical applications Chokeberry juice is a popular, widespread product of chokeberry fruit characteristic for the dark intense red color, slightly unpleasant, bitter taste and extremely rich bioactive compounds content. Because of high nutritional quality, chokeberry juice is often consumed but with the biggest barrier of characteristic astringent taste which can be diminished by addition of sweetener. Producers often combine a low‐cost sweeteners like sucrose which shows numerous negative effects on human health. A good alternative to the sucrose and artificial sweeteners are natural sweeteners extracted from the plant material like steviol glycosides. Except sweetness, stevia products like green powder shows beneficial effect on the bioactive compounds content in the juices sweetened with it. Juices sweetened with stevia shows increased content of bioactive compounds, so such product may represent quality product from category of functional food.

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