红茶果醋发酵工艺优化

为确定红茶果醋的最佳工艺参数,本试验以红茶、石榴为原料,接种酵母菌、醋酸菌进行发酵。在单因素实验的基础上,以茶果汁比、酵母菌接种量、加糖量为因素进行酒精发酵阶段的正交实验,以初始酒精度、醋酸菌接种量、发酵温度为因素进行醋酸发酵阶段的正交实验。结果表明:优化后的最佳工艺条件为:酒精发酵阶段,微波浸提4 min,茶水比5:100,茶果汁比1:5,酵母菌接种量0.2%,加糖量16 g/100 mL;醋酸发酵阶段,装瓶量30%,初始酒精度7%vol,醋酸菌接种量12%,30℃发酵。在此条件下,发酵的红茶果醋总酸含量为6.48 g/100 mL、茶多酚含量为397.85 mg/L,富含16种氨基酸,总含量为5.93 mg/mL,其中必需氨基酸占总含量的38.45%,其色泽明亮、香气协和、风味独特,理化及卫生指标符合国家相关标准。本研究结果可为红茶果醋的开发和工业化生产提供理论依据。     

不同品种石榴籽油组分及抗氧化性研究

以白色甜味,红色甜味和红色酸味3种石榴栽培品种(分别为临潼‘三白甜’(SBT)、‘净皮甜’(JPT)和‘酸石榴’(SSL))的果实为原料,通过石油醚超声波辅助提取法获得籽油样品,采用气相色谱-质谱法(GC-MS)分析其脂肪酸组成的差异性,并研究这些籽油的自由基清除能力及其皂化产物的抗氧化性。结果表明:3种石榴籽油(PSO)的主要组分的含量差异较大,含量最高的脂肪酸均为石榴酸,其含量大小顺序为‘三白甜’籽油‘净皮甜’籽油‘酸石榴’籽油。3种石榴籽油对DPPH·和ABTS+·均有较强的清除作用,且呈量效关系,其皂化产物(脂肪酸盐)则具有良好清除·OH和抑制β-胡萝卜素/亚油酸体系漂白的作用,而且3种油及其皂化产物的抗氧化性强弱排序相同,均为SBTJPTSSL,这提示石榴籽油中的石榴酸最可能是其关键的抗氧化成分。这些发现可为石榴籽油的进一步研发提供依据。     

微波辐射提取石榴皮单宁的研究

以丙酮为提取溶剂,采用微波辐射提取石榴皮中的单宁,考察了溶剂浓度、微波功率、微波辐射时间、液料比等因素对单宁提取量的影响。结果表明,当溶剂体积浓度50%、微波辐射功率320 W、微波辐射时间5 m in和液料比18∶1(g/g)时,单宁的提取量为268.54 mg/g,比普通水浴提取提高了30.39 mg/g。     

提取方法和溶剂对石榴皮中抑菌成分提取的影响

探讨了石榴皮中抑菌成分的提取方法.分别以水、40％乙醇、60％乙醇和丙酮作为溶剂,采用微波提取法、超声波提取法、加热回流提取法对石榴皮中抑菌成分进行提取;并考察提取物对大肠杆菌和金黄色葡萄球菌的抑菌作用.结果表明:以60％乙醇作为溶剂时,微波提取物和超声波提取物的抑菌活性比加热回流提取物高,且具有提取时间短、效率高等特...     

Quality and antioxidant properties of a reduced-sugar pomegranate juice jelly with an aqueous extract of pomegranate peels

In the present study, the production of a reduced-sugar pomegranate juice jelly supplemented with an aqueous extract of pomegranate peel (PE) is described. Influence of different carbohydrate polymers (guar (G), xanthan (X) and tragacanth (T) gums) on rheological properties was studied. Combination GXT presented the most similar rheological behaviour to commercial jelly. Jelly (J) and jelly with PE (JE) were stored at 4 °C over an 8 week period for physical, chemical, antioxidant, microbiological and sensory analysis. J and JE showed similar values for °Brix, colour and Aw, though the pH of JE was lower than J. Thiol and phenolic compounds were higher in JE than in J. Antioxidant activity (radical scavenging activity and autoxidation of linoleic acid) was higher in JE than in J at 0 weeks, and were decreasing with time. Pomegranate juice with additives was generally less accepted than J and JE.     

干酪素法测定新疆不同产地石榴皮中鞣质的含量

建立采用干酪素法测定石榴皮中鞣质含量的方法。结果表明,鞣质含量在1.02～6.12μg/ml范围内呈线性关系,r=0.9993;方法平均加样回收率为97.4%,RSD=1.21%(n=6)。和田地区的皮山和策勒两县石榴皮鞣质含量略低于喀什地区的疏附、疏勒和叶城地区。此方法准确可靠、重现性好,可以作为石榴皮药材质量控制的方法。     

石榴花色苷的微波辅助提取及抗氧化活性研究

以陕西临潼甜石榴为试验材料,通过正交试验,采用pH 差示法测定石榴总花色苷含量,优化微波辅助提取石榴花色苷的工艺参数。同时,采用DPPH 法、FRAP 法、ABTS 法、螯合亚铁能力法分析石榴花色苷的体外抗氧化活性。结果表明：微波辅助提取石榴花色苷的最佳工艺参数为溶剂pH1、料液比1:13(g/mL)、提取时间210s、乙醇体积分数70%、微波输出功率360W。此条件下,花色苷得率为184.81μg/g。微波输出功率对石榴汁花色苷的提取得率有显著影响(P ＜ 0.05)。石榴花色苷含量与DPPH 自由基清除率、铁还原力、ABTS+ 自由基清除率和螯合亚铁离子有显著的相关性(相关系数R2 分别为0.9928、0.9925、0.9913、0.9945),呈明显的量效关系,IC50 值分别为2.44、1.14、4.08、101.05mg/L。     

新疆石榴花中红色素理化性质的研究

对新疆石榴花中红色素的提取及对其物理化学性质进行了研究。     

Physico-Chemical,antioxidant activities,textural, and sensory properties of yoghurt fortified with different states and rates of pomegranate seeds (Punica granatum L.)

This study examines the effects of incorporating fresh, frozen, osmodehydrated, and dried pomegranate seeds, at different concentrations (5, 10, and 20%) on the physicochemical, antioxidant, textural, and sensory properties of yoghurt. Antioxidant activity, pH, acidity, syneresis, and color of yoghurt were also evaluated during the storage (28 days) at 4°C. The principal component analysis (PCA) was performed to assess the correlations between different yoghurt formulation and their sensory attributes. Data showed that the addition of pomegranate seeds reduced pH and modified the chromatics coordinate (L*, a*, b*, C*, h°) and firmness of the yoghurt samples. In addition, acidity, °Brix, and syneresis increased compared to the control. Thanks to their high anthocyanin content, pomegranate seeds considerably improved the antioxidant activity essentially for yoghurt enriched with frozen seeds. In addition, the supplementation of 20% of frozen seeds into yoghurt was the most appreciated by panelists and improved the sensory properties in comparison to other formulation. According to PCA, taste and appearance were the main criteria for the overall acceptability of yoghurt. After 28 days of storage, the reddish color was reinforced; however, the antioxidant activity of yoghurts was reduced. Overall, it can be concluded that pomegranate seeds can be used as a natural ingredient to develop a novel yoghurt with high nutritional properties.