蓝莓酒中菌落总数测量不确定度的分析

依据GB 4789.2-2010《食品安全国家标准食品微生物学检验菌落总数测定方法标准》,通过对蓝莓酒中菌落总数的测量结果,对不确定度的因素进行评估,研究了测量不确定度对细菌总数检验过程准确性的验证。     

蓝莓浓缩汁流变特性及化学组成的变化

流体的流变学可为工艺设计提供有关数据,并有助于找出产品组成及加工工艺对流变性质的影响。本研究采用AR1000型流变仪研究了浓缩蓝莓汁(60°Brix)在(20～60℃)范围内的流变特性。通过回归分析发现,在研究的温度和浓度范围内,浓缩蓝莓汁表现为牛顿型流体,温度对粘度的影响可用阿雷尼乌斯(Arrhenius)方程来表示,浓度对粘度的影响可用指数方程来表示。推导出了温度和浓度对浓缩蓝莓汁粘度综合影响的方程式并比较了浓缩前后蓝莓汁化学组成的变化。     

高压脉冲电场和热处理对蓝莓汁品质的影响

以蓝莓汁为原料,比较了高压脉冲电场（PEF）杀菌和热力杀菌处理对蓝莓汁中微生物和理化指标的影响,以及不同处理的蓝莓汁在贮藏期间的品质变化规律。结果表明：PEF可以有效杀灭蓝莓汁中的微生物;PEF杀菌对蓝莓汁色泽参数影响程度小;杀菌处理后,贮藏期内PEF处理和热处理对蓝莓汁的还原糖、总酸、可溶性固形物含量、总酚含量影响较小,PEF处理较热处理能更好地保持蓝莓汁中的VC和花青素含量。     

酵母的固定化及在蓝莓酒发酵中的应用

为了研究固定化酵母的优越性,将固定化酵母与游离酵母进行比较。用加有SiO2和Al2O3的壳聚糖-海藻酸钠和加有SiO2和Al2O3的PVA-海藻酸钠载体进行实验,确定较优的载体。测定海藻酸钠、PVA、SiO2和Al2O3的最适添加量,通过正交实验,确定最佳工艺条件。结果表明:海藻酸钠浓度为1.5%,PVA添加量为0.6%,Al2O3添加量为0.8%,SiO2添加量为1.4%时,发酵效果最好,发酵周期短,为3d,蓝莓酒风味也最好。因此,用加有SiO2和Al2O3的PVA-海藻酸钠载体发酵得到的蓝莓酒各方面性质最好。     

酰基化蓝莓花色苷的稳定性和对氧自由基清除能力

由于天然花色苷稳定性差,严重阻碍了其在食品工业中的广泛应用。为了改善花色苷的稳定性,采用分子修饰的方法,通过酰基化反应修饰蓝莓花色苷,并研究酰化后蓝莓花色苷的光、热稳定性和对氧自由基的清除能力。通过紫外吸收光谱和红外光谱表明蓝莓花色苷已经酰基化。相对未酰化的蓝莓花色苷,酰基化蓝莓花色苷的光、热稳定性显著提高,但清除羟基自由基、超氧阴离子自由基的能力略有下降,清除羟自由基、超氧阴离子自由基的IC50分别为0.74、3.14mg/mL。     

超高压和热处理对蓝莓汁品质的影响

以蓝莓汁为原料,进行了超高压(UHP)和热力处理对蓝莓汁微生物和理化指标的影响,以及贮藏期内蓝莓汁品质变化的研究。结果表明:超高压可以有效杀灭蓝莓汁中的微生物;超高压处理后,蓝莓汁表现出更诱人的颜色;贮藏期内超高压和热处理对蓝莓汁的总酸、还原糖、可溶性固形物含量影响较小;与热处理相比,超高压处理能更好的保持蓝莓汁中的VC和花青素含量。     

Susceptibility of anthocyanins to ex vivo degradation in human saliva

Some fruits and their anthocyanin-rich extracts have been reported to exhibit chemopreventive activity in the oral cavity. Insights regarding oral metabolism of anthocyanins remain limited. Anthocyanin-rich extracts from blueberry, chokeberry, black raspberry, red grape, and strawberry were incubated ex vivo with human saliva from 14 healthy subjects. All anthocyanins were partially degraded in saliva. Degradation of chokeberry anthocyanins in saliva was temperature dependent and decreased by heating saliva to 80 °C and after removal of cells. Glycosides of delphinidin and petunidin were more susceptible to degradation than those of cyanidin, pelargonidin, peonidin and malvidin in both intact and artificial saliva. Stability of di- and tri-saccharide conjugates of anthocyanidins slightly, but significantly, exceeded that of monosaccharide compounds. Ex vivo degradation of anthocyanins in saliva was significantly decreased after oral rinsing with antibacterial chlorhexidine. These results suggest that anthocyanin degradation in the mouth is structure-dependent and largely mediated by oral microbiota.     

Antioxidant anthocyanins screening through spectrum-effect relationships and DPPH-HPLC-DAD analysis on nine cultivars of introduced rabbiteye blueberry in China

Blueberries have drawn growing attention in China for various benefits to health. Nine rabbiteye blueberry cultivars which were introduced into China were systematically assessed based on two aspects of chemical profiles and antioxidant activity. The former was achieved by HPLC fingerprints, and the latter in terms of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging capacity was evaluated with a novel HPLC method. Subsequently, the predominant active anthocyanins were screened from these coloured biological samples by two useful methods, respectively. In method I, the spectrum-effect relationships between HPLC fingerprints and the antioxidant activities of blueberry extracts were investigated, whereas in method II, HPLC analysis followed pre-column reaction of samples with DPPH. The results indicated that Gardenblue and Powderblue showed stronger antioxidant activities among all introduced cultivars, and delphinins and anthocyanidin-3-glucosides were the main contributive components to the antioxidant activities of blueberries. This would be helpful to the quality-oriented cultivation of blueberry in China.     

High performance liquid chromatography analysis of anthocyanins in bilberries (Vaccinium myrtillus L.), blueberries (Vaccinium corymbosum L.), and corresponding juices

In the present study the anthocyanin content of commercially available bilberry juices and fresh fruits were quantified by using 15 authentic anthocyanin standards via high performance liquid chromatography with an ultra-violet detector (HPLC-UV/VIS). Delphinidin-3-O-glucopyranoside, delphinidin-3-O-galactopyranoside, and cyanidin-3-O-arabinopyranoside were the major anthocyanins found in juices, nectar, and fresh bilberries. In contrast, fresh blueberries had higher concentrations of malvidin-3-O-arabinopyranoside and petunidin-3-O-galactopyranoside. Up to 438 mg anthocyanins per 100 g fresh weight (2762 mg/100 g dry weight (DW)) were detected in blueberries from various sources, whereas bilberries contained a maximum of 1017 mg anthocyanins per 100 g fresh weight (7465 mg/100 g DW). Commercially available bilberry and blueberry juices (n= 9) as well as nectars (n= 4) were also analyzed. Anthocyanin concentrations of juices (1610 mg/L to 5963 mg/L) and nectar from bilberries (656 mg/L to 1529 mg/L) were higher than those of blueberry juices (417 mg/L) and nectar (258 mg/L to 386 mg/L). We conclude that using several authentic anthocyanin references to quantify anthocyanin contents indicated them to be up to 53% and 64% higher in fresh bilberries and blueberries, respectively, than previously reported using cyanidin-3-O-glucoside. This study has also demonstrated that commercially available juices produced from bilberries contain much higher anthocyanin concentrations than those from blueberries. PRACTICAL APPLICATION: We have investigated the contents of a special class of antioxidants, namely anthocyanins in blueberry and billberry fruits and juices commercially available in Germany. To achieve reliable data we have used authentic standards for the first time. We think that our results are important in the field of nutritional intake of this important class of polyphenols and fruit juice companies get a closer insight in the occurrence of these antioxidants in market samples to be used in food composition databases and for nutritional survey.     

人参蓝莓口嚼片的研制

精选白参经过超声波提取,得到人参提取物。蓝莓经过榨汁、喷雾干燥制成蓝莓果汁粉。以人参提取物和蓝莓果汁粉为主要原料,淀粉、木糖醇等为辅料,以40%乙醇作为润湿剂,经压片而制成的一种新型口嚼片。通过单因素和正交试验,确定最佳工艺条件和配方。结果表明,人参提取物添加量为15%、蓝莓果汁粉添加量35%、淀粉添加量为20%、40%乙醇添加量为40%。