Evolution of anthocyanins during vinification of Merlot and Pinot Noir grapes to wines

The evolution of individual anthocyanins during vinification of Merlot and Pinot Noir grapes was studied using two different winemaking procedures for each grape variety. Additionally, the effect of the applied vinification on the anthocyanin composition of the obtained wine at the end of maceration and wine aged 6 months was investigated and compared with the anthocyanin patterns of the original grape. The dynamics of the extraction process was monitored daily during maceration by analysing the anthocyanins in the must using HPLC. The results showed that the anthocyanin composition of young wines was different from that of the grapes. The proportions of malvidin-3- glucoside and malvidin-acetate were higher in wines than in the grape skins, but this was not the case for malvidin coumarate. Application of different vinification procedures to the same raw material resulted in wines with similar anthocyanin patterns. However, the anthocyanin profiles changed with the ageing of the wines

Enzyme‐assisted aqueous extraction of Kalahari melon seed oil: optimization using response surface methodology

Enzymatic extraction of oil from Kalahari melon seeds was investigated and evaluated by response surface methodology (RSM). Two commercial protease enzyme products were used separately: Neutrase® 0.8 L and Flavourzyme® 1000 L from Novozymes (Bagsvaerd, Denmark). RSM was applied to model and optimize the reaction conditions namely concentration of enzyme (20–50 g kg−1 of seed mass), initial pH of mixture (pH 5–9), incubation temperature (40–60 °C), and incubation time (12–36 h). Well fitting models were successfully established for both enzymes: Neutrase 0.8 L (R 2 = 0.9410) and Flavourzyme 1000 L (R 2 = 0.9574) through multiple linear regressions with backward elimination. Incubation time was the most significant reaction factor on oil yield for both enzymes. The optimal conditions for Neutrase 0.8 L were: an enzyme concentration of 25 g kg−1, an initial pH of 7, a temperature at 58 °C and an incubation time of 31 h with constant shaking at 100 rpm. Centrifuging the mixture at 8,000g for 20 min separated the oil with a recovery of 68.58 ± 3.39%. The optimal conditions for Flavourzyme 1000 L were enzyme concentration of 21 g kg−1, initial pH of 6, temperature at 50 °C and incubation time of 36 h. These optimum conditions yielded a 71.55 ± 1.28% oil recovery

Extrakce silice z řebříčku superkritickým CO2

Flowers of yarrow were extracted with supercritical carbon dioxide using onestage sub-critical separation. The process was conducted to optimize conditions for obtaining essential oil free of waxes. The effectiveness of the process was compared with hydrodistillation. It was established that particle size has no influence on extraction yields

Complexity and health functionality of plant cell wall fibers from fruits and vegetables

The prevalence of lifestyle-related diseases is increasing in developing countries with the causes for death starting to follow the same pattern in the developed world. Lifestyle factors including inadequate dietary intake of fruits and vegetables and over consumption of nutrient-poor processed foods, are considered to be major causal risk factors associated with increased susceptibility to developing certain diseases (Alldrick, 1998; Kiani, 2007). Recent epidemiological evidence confirms a strong association between dietary fiber and reduced all-cause mortality risk, as well as a risk reduction for a number of non-communicable diseases (Chuang et al., 2012). The relationship between dietary fiber and mortality has been described as “convincing observations that call for mechanistic investigations” (Landberg, 2012). In particular, the health protective roles played by dietary fibers of different origin are not well understood. Whilst Hippocrates was the earliest known physician to study the health benefits of fiber derived from grains (Burkitt, 1987), the functionality of fruit and vegetable fiber, especially in association with other compounds such as polyphenols and carotenoids, is an area of more recent interest. Hence the objective of this review is to assess the complexity and health-related functional role of plant cell wall (PCW) fibers from fruits and vegetables with a particular emphasis on interactions between cell walls and phytonutrients