Qualitative comparison of blackcurrant and blackcurrant--whey beverages

This study provides a qualitative comparison of blackcurrant and blackcurrant-whey beverages over a 12-month storage period. The amount of extract in the beverages was established as 12%, of which 25% was blackcurrant concentrate. Acid whey was used for the production of blackcurrant-whey beverages. In comparison to blackcurrant-whey beverages, blackcurrant beverages contained significantly more glucose, fructose, sucrose, polyphenols and vitamins C and B1. They also had a higher level of antioxidant activity against ABTS•+ and DPPH, with the difference ranging from 2% to 46%. On the other hand, blackcurrant-whey beverages contained more ash, proteins and vitamin B2 and the presence of lactose was detected. They were also characterized by higher color parameter values evaluated according to the CIE system. A general sensory evaluation awarded blackcurrant beverages with 0.5-1.3 more points than blackcurrant-whey beverages. A descriptive flavor analysis found that blackcurrant taste dominated in both types of beverages; however, in blackcurrant-whey beverages, the taste and smell of whey were also discernible. Changes in the quality of the beverages were observed during the storage period, notably a decrease in their antioxidant properties.

Effect of aronia berry honey syrup used for sweetening jams on their quality

The effects of sweetening agents on the quality of low sweetened jams were compared with respect to blackcurrant, raspberry, sour cherry, strawberry, and bilberry jams. The sweetening agents were sucrose, aronia berry honey syrup, and sucrose + honey syrup at a ratio of 1:1. The level of physicochemical indices, especially the content of vitamin C and anthocyanins determined directly after production and after 3- and 6-month storage, was used as the quality criterion for the evaluation of jams. Moreover, after 6-month storage the products were subjected to sensorial analysis. According to the accepted method of the investigation the produced jams were characterized by a 32-33% content of extract. During the production and 6-month storage the content of acids slightly and that of pectin considerably (from 26 to 46%) decreased, although the consistency of the jams was not affected thereby. In the case of vitamin C, its pronounced losses concerned raspberry (62-67% of the initial value), strawberry (57-61%), and sour cherry (57-58%), being distinctly smaller in blackcurrant (13-16%) and bilberry (15-35%) jams. With respect to anthocyanins a similar regularity was observed, the losses reaching 49-63% in strawberry jam, 40-56% in raspberry, 33-39% in sour cherry, 30-36% in blackcurrant, and 28-36% in bilberries. In almost all the products the losses of vitamin C and anthocyanins were higher when sweetening agent was aronia berry honey syrup. The organoleptic evaluation showed that the addition of aronia berry honey syrup to raspberry and strawberry jams slightly spoiled their colour but improved the aroma and taste. In the final score the significant differentiation in favour of the addition of aronia berry honey syrup concerned only blackcurrant, sour cherry, and bilberry jams.

[Comparison of the quality of frozen raspberries depending on the use of various additives]

The aim of the study was to determine the effect of sugar, pectin preparation, and L-ascorbic acid addition on selected physicochemical traits and organoleptic properties of frozen raspberries. Dry sugar or in the form of 60% syrup at a dose of 10 g/100 g of fruit was used with pectin or 0.5% L-ascorbic acid. A 1.5%. solution of the pectin preparation was applied at a dose of 10 g/100 g of fruit alone or with a 0.5% addition of L-ascorbic acid. Sorted fruits in 500 g samples treated with additives were frozen in plastic containers at -40 C, the storage temperature of -28(-)-30 C being reached after about 90 min. The evaluation was conducted at a stage of raw material, directly after freezing, and after 3-, 6-, 9-, and 12-month storage. Fresh fruit contained 13.4% of dry matter, 4.1% of total sugars, 2.12% of acids as citric acid, 48.3 mg/100 g of vitamin C, and 60.8 mg/100 g of anthocyanins. The additives contributed to the differentiation of frozen fruit samples in the level of dry matter, sugars, and vitamin C, and brought about some dilution of the remaining components. Freezing and 1-year storage of fruit not treated with any additives decreased the content of vitamin C in 100 g to 21.6 mg and of anthocyanins to 45.5 mg. In the samples with the additives these values were 23.4-29.2 mg /the samples of an enriched vitamin C content not being taken into consideration/and 47.1-56.3 mg, respectively. The organoleptic quality of frozen raspberries without additives evaluated in a 5-score scale was 3.78 and that of fruit with the additives 4.21-4.74. Of the analyzed variants of the additives used in freezing raspberries for direct consumption the 60% syrup of sucrose may be recommended on account of high organoleptic quality and simple application. The 1.5% solution of pectin preparation may be used in freezing raspberries for diabetics and the other groups of people who do not tolerate sugar in their diet.