β-glucosidase Activity in Juice-Processing Enzymes Based on Anthocyanin Analysis

A screening procedure utilizing boysenberry juice as a substrate, which combined HPLC and spectrophotometric analyses, was used to measure β-glucosidase activity of enzyme preparations used for juice processing. Enzyme preparations (n = 26) were evaluated at two dosage rates. At the mean recommended dosage, one preparation produced a decrease in total monomeric anthocyanin and cyanidin-3-glucoside, relative to a control, indicating β-glucosidase activity. At 0.1% dosage, 4 enzymes produced a significant decrease in cyanidin-3-sophoroside and 2 enzymes caused an increase in cyanidin-3-rutinoside, indicating β-1,2-glucosidase activity. Such activity in juice processing enzymes was much lower and less prevalent than found previously for β-galactosidase. Botrytis cinerea also degraded anthocyanins in boysenberry juice.     

Mass spectrometry fragmentation pattern of coloured flavanol‐anthocyanin and anthocyanin‐flavanol derivatives in aged red wines of Rioja

Background and Aims: During wine ageing, a great variety of reactions take place, resulting in an immense variety of products whose structure sometimes remains unknown. The aim of this work is the study of different fragmentation patterns of flavanol‐anthocyanin derivatives formed along the wine ageing; these patterns are useful for elucidating the different structures of these compounds and other new related ones. Methods and Results: Several wines from the Protected Denomination of Origin Rioja have been studied by an analytical method that combines column chromatography and high‐performance liquid chromatography with diode array and mass and tandem mass spectrometric detections. Thirty‐five coloured flavanol‐anthocyanin compounds formed by direct reaction or by acetaldehyde‐mediated condensation have been identified. For direct reaction derivatives, two different fragmentation patterns (one of them not previously reported) have been observed depending on the position of flavanol in the coloured derivative. Several compounds have been identified in aged wines for the first time to the authors' knowledge, like (+)‐gallocatechin‐cyanidin‐3‐glucoside and (+)‐catechin‐cyanidin‐3‐glucoside Conclusions: The developed analytical procedure has allowed the identification of some compounds for the first time, and two different fragmentation patterns have been observed depending on the position of flavanol in the pigment. Significance of the Study: The establishment of different fragmentation patterns allows the structural elucidation of unknown compounds.     

Anthocyanins remain stable during commercial blackcurrant juice processing

Abstract: It remains important to establish the stability of anthocyanins throughout commercial processing in order to maintain the bioactivity of the processed food/s. The present study aimed to assess the recovery and formation of anthocyanins and their free phenolic acid degradation products during the commercial processing of blackcurrant juice concentrate. A bench‐scale processing model was also established to allow for alteration of predefined parameters to identify where commercial processes could be modified to influence anthocyanin yield. No significant loss in anthocyanins was observed throughout the commercial processing of blackcurrants, from whole berry through milling, to pectin hydrolysis and sodium bisulphite addition (P ≥ 0.7). No significant loss in anthocyanins was observed following the subsequent processing of pressed juice, through pasteurization, decantation, filtration, and concentration (P ≥ 0.9). Similarly, the bench‐scale model showed no significant losses in anthocyanin content except during pasteurization (22%± 0.7%, P < 0.001). In the full‐factorial Design of Experiment model analysis, only sodium bisulphite concentration had an impact on anthocyanin recovery, which resulted in an increase (23% to 27%; P < 0.001) in final anthocyanin concentration. No phenolic degradation products (free protocatechuic acid or gallic acid derived from cyanidin and delphinin species, respectively) were identified in any processed sample when compared to authentic analytical standards, analyzed by ultra‐performance liquid chromatography DAD. Practical Application: This article provides crucial data directly applicable to commercial juice processing, such as improving anthocyanin yield and practical considerations for anthocyanin stability and degradation. This aspect is particularly pertinent considering the current commercial interest in anthocyanin‐derived phenolic acids and their health‐related benefits. Further research and development targets in the area of commercial juice product development are identified.     

响应面分析法优化超声辅助提取红肉苹果花青苷工艺

采用响应面分析法优化超声波辅助提取红肉苹果花青苷的提取工艺。以花青苷的含量作为响应值,在单因素试验基础上,根据Box-Behnken中心组合试验设计原理采用4因素3水平的响应面分析法对各因素进行分析,结果表明,红肉苹果花青苷的最佳提取条件为丙酮体积分数80%,料液比1∶14(g∶mL),超声时间32min,盐酸含量1.2%,在此条件下提取的花青苷的质量浓度为7.01mg/100mL,与响应面预测理论值(7.09mg/100mL)相当。     

响应面法优化超声提取黑果腺肋花楸花色苷工艺的研究

为优化超声提取黑果腺肋花楸花色苷的工艺条件,在对料液比、提取温度、乙醇体积分数、提取时间、超声功率5个单因素试验的基础上,采用Minitab 15.0软件设计回归正交试验,用响应面法分析优化各因素及其相互作用对花色苷得率影响的最佳组合,得出超声提取黑果腺肋花楸花色苷最佳提取参数为提取液乙醇体积分数80％,提取温度50℃,提取时间48 min,在此条件下黑果腺肋花楸果花色苷提取量为39.80 mg/g.     

Effect of Dehydration on Raspberries: Polyphenol and Anthocyanin Retention, Antioxidant Capacity, and Antiadipogenic Activity

ABSTRACT:  Fresh and dried raspberries prepared by freeze drying (FD), microwave-vacuum (MIVAC), hot-air drying (HAD), and a combination of hot-air drying and microwave-vacuum (HAD/MIVAC) drying methods were evaluated for polyphenol retention, total polyphenol and anthocyanin contents, total antioxidant capacity, and antiadipogenic activity (the inhibition of fat cell development). Ellagic acid and quercetin were present in the largest concentrations in fresh and dehydrated raspberries. Dehydration led to a loss of polyphenols and anthocyanins and antioxidant capacity. Polyphenols (aglycone form) were retained in the greatest amount: 20% (freeze dried) to 30% (HAD/MIVAC) (fresh = 100%). A total of 30% of polyphenols (glycoside form) were retained in raspberries dried by the HAD/MIVAC methods with 5% of retention observed for raspberries dried by FD, HAD, or MIVAC. FD and MIVAC resulted in higher retention of anthocyanins (aglycone form) than other drying methods. It was also observed that antioxidant activity was reduced by dehydration. Adipogenesis was inhibited by polyphenolic glycosides (30%) and aglycones (30% to 40%) in fresh and HAD/MIVAC raspberries. Extracts from dried raspberries by HAD/MIVAC methods were relatively more effective at inhibiting adipogenesis compared to HAD and FD dried raspberries.     

Involvement of Anthocyanins and other Phenolic Compounds in Radical-Scavenging Activity of Purple-Fleshed Sweet Potato Cultivars

ABSTRACT: The 80% ethanol extracts of 5 purple-fleshed sweet potato cultivars were separated into 2 fractions, anthocyanins- and phenolic compounds-rich fractions, to clarify the contribution of these constituents to the radical-scavenging activity. The separation was accomplished with an ethyl acetate liquid/liquid extraction. 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity in each fraction and the contributors varied according to the cultivars. The dominant DPPH radical-scavengers in "Ayamurasaki" and "Kyushu-132" were anthocyanins rather than phenolic compounds, while those in "Miyanou-36" and "Bise" were phenolic compounds, such as chlorogenic acid. Furthermore, the high-performance liquid chromatography analysis of anthocyanins showed that "Ayamurasaki" and "Kyushu-132" were rich in anthocyanins with peonidin aglycon, whereas "Miyanou-36,""Bise," and "Tanegashimamurasaki" contained cyanidin aglycon.