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» Articles | Agricultural Journals

An effect of a processing method (dry and wet) and a degree of roasting (light, medium, and dark) of 15 coffee (Coffea arabica) samples on the content of caffeine, chlorogenic acid (CQA), total polyphenols (TPP), acrylamide (AA), and on the colour parameters L*, a*, and b* was evaluated. Neither processing nor roasting affected caffeine content (p > 0.05). The degree of roasting accounted for 46% and 72% of explained variability of the CQA content and AA content, respectively (p < 0.05). AA content was in the range from 250 (wet-processed, light-roasted samples) to 305 µg·kg⁻¹ (wet-processed, dark-roasted coffees), but the dark roasting only tended (p > 0.05) to increase AA content. Wet-processed, dry-roasted coffee had higher (p < 0.05) TPP content (48.5 mg·g⁻¹) than its dry-processed, dry-roasted counterpart (42.5 mg·g⁻¹); the method of processing accounted for 70% of explained variability of TPP. Both the method of processing and the degree of roasting affected the L*, a*, and b* values (p < 0.01), but the lower values (p < 0.05) of these parameters in the dark-roasted samples were found only within the wet processing. A negative correlation between the AA content and lightness (L*) was established (r = −0.39, p < 0.05). It was concluded that from the consumers’ viewpoint, the results of the present study indicate relatively small differences in quality parameters of coffee irrespective of the method of processing or degree of roasting.

The influence of the drying technique on certain quality attributes of dried grapes was analysed. Five varieties of grape were used in this study (Bezsemenné, Perlette, Vrboska, Beauty seedless, and Jakubské). All the varieties were dried using four methods: drying at 40 °C, combined drying (70, 65, and 60 °C), drying at 70 °C, and lyophilisation. The quality attributes such as total soluble solids, water activity, content of vitamin C, the colour parameters (L*, a*, b*), and microbiological (colony forming units, moulds, yeasts) and sensory (smoothness, gloss, colour, odour, chewability, juiciness, flavour, and overall impression) analysis were determined, depending on the method of drying. Lyophilised grapes from the Jakubské variety had the highest vitamin C content. They contained 0.58 mg of vitamin C per 100 g of dried grapes. However, no significant differences between varieties in vitamin C content were found. This confirmed concerns about the negative impact on the nutritional quality of dried grapes with increasing temperature. The lowest total count of microorganisms (CFU), moulds, and yeasts were determined after using highest drying temperature (70 °C). Higher CFU values were determined in lyophilised grapes, and then followed by grapes dried at 40 °C. Lyophilised grapes and grapes dried at 40 °C achieved the best sensory rating in general. The final product was intended to have a unique appearance while maintaining the evaluated quality parameters.

The purpose of the present study was to ascertain whether it is possible to substitute animal protein in a pig diet with lupine of Sonet cultivar or amaranth grain or dried surface biomass of amaranth when one type feed ration is used during the entire period of fattening, and to investigate its impact on growth efficiency and health of pigs. Its role in feed conversion, carcass characteristics, meat quality and sensory parameters was analyzed. Four groups of pigs (n = 10, 5 males and 5 females) with the body weight of 24 kg were fed semi-ad libitum for 90 days the following diets: control group (C) - diet containing 3% of fish meal, experimental group (1) - diet containing 5% of non-heat-treated amaranth grain and 5% of dried surface biomass of amaranth, experimental group (2) - diet containing 5% of popped (heattreated) amaranth grain and 5% of dried surface amaranth biomass, experimental group (3) - diet containing 10% of lupine seed meal. Animal protein substitution in diets with amaranth (group 1, 2) or lupine (3) did not result in significant differences ( p > 0.05) in average daily body weight gain in comparison with the control group (C - 0.83 and 0.82, 0.80 and 0.79 kg in groups 1, 2 and 3, respectively). The differences in feed conversion were non-significant (2.69 to 2.79 kg/kg of body weight gain). The tested diets did not adversely affect animal metabolism, and significantly lower concentrations ( p < 0.05, p < 0.01) of total protein, glucose and triacylglycerol in animals of group C ranged within physiological limits. No significant differences between control and experimental animals were found in carcass characteristics, meat and sensory qualities. Lupine supplementation of the diet positively affected the tenderness and taste of meat.

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