Characterization of mulberry leaf instant tea and evaluation of its hypolipidemia effect via regulation of intestinal microbiota

The purpose of this study was to characterize mulberry leaf instant tea(MLIT)powder prepared from the'Longsang No.1'(Morus abla L.cv.Longsang 1)mulberry leaves in Heilongjiang Province(China)and assess its obesity-preventing/relieving effects.A total of 174 compounds including quercetin,chlorogenic acid,1-deoxyecomycin(1-DNJ)related to antihyperlipidemia effects were identified from the MLIT powder.MLIT treatment reversed the Lee's index,fat coefficient,and serum biochemical parameters in both the obesity relieving and obesity preventing mice fed with high-fat diet.In the obesity relieving experiment,the relative abundance of Desulfovibrio in mouse feces decreased after both 0.5%and 1%MLIT treatments.In obesity preventing experiments,mouse with different amount of MLIT treatments showed increased relative abundance of Akkermansia,Bifidobacterium and Lactobacillus,while Deferribacteres,Desulfobacterota decreased.The beneficial bacteria in the intestinal tract of mice treated with MLIT increased.This study proved that MLIT had antihyperlipidemia potential via modulating intestinal microbiota in mice.

Development and Processing of Millettia speciosa Instant Tea

This paper analyzed the effect of raw material crushing fineness,cooking time,ethanol content during ethanol precipitation and other factors on the preparation of raw material extract from Millettia speciosa Champ. instant tea. The raw materials of Millettia speciosa Champ.,Philippine flemingia root and radix fici simplicissimae were crushed into 10 mesh or finer powder,and cooked for 60 min. During ethanol precipitation,the ethanol content was about 50% to 70%,standing 12 h. The ophiopogon root was cooked in 1∶ 15 boiling water for 45 min,and chrysanthemum was leached for 45 min with 1∶ 20 demineralized water at 80 ℃. After concentration,preparation and spray drying,the finished Millettia speciosa Champ. instant tea was created. The detection of each product index indicated that Millettia speciosa Champ. instant tea had good taste and flavor,and there were no heavy metals,harmful substances and excessive microbes,thereby showing that the raw material of Millettia speciosa Champ. instant tea was selected reasonably,the mixture ratio was rational,and the processing technology was of some security,stability and maturity,which provided a theoretical basis for its development and application.

Study on the Preparation of"Oil-tea"Instant Tea from the Compound Extract of Green Tea and Ginger

[Objectives]This study was conducted to develop an"oil-tea"instant tea with traditional"oil-tea"flavor,easy preservation and transportation and good taste.[Methods]With green tea,ginger and peanuts as experimental materials,a compound extract was obtained by boiling,and the"oil-tea"instant tea was prepared by spray drying.The tea polyphenol content and soluble solid content of the extract(oil tea soup),the yield of finished solid product and sensory quality were comprehensively evaluated.[Results]The optimum instant tea technical parameters were determined as follows:the ratio of material to liquid 1∶15,the extraction time of boiling 60 min,the inlet air temperature of spray drying 180℃,the feeding speed 850 ml/h,the soluble solid content of the extract 13%,and the amount of maltodextrin added 12 mg/g.Under these conditions,the yield of the instant tea was high,and the instant tea had better sensory quality and good solubility.[Conclusions]This study provides a reference for the commercial development of"oil tea".

Effects of 60Co-γ Ray Radicidation on Instant Tea

Effects of 60Co-γray radicidation on instant tea were studied through contaminant microbe assay, absorbed dose measurement and analysis of principal components of instant tea.

High-quality instant black tea manufactured using fresh tea leaves by two-stage submerged enzymatic processing

Repeated thermal treatment could impair the flavor of instant black tea(IBT)as the volatile compounds and characteristic constituents dramatically vary during the manufacturing process.Utilization of fresh leaves as raw material in IBT manufacture at low temperature may become an alternative to conventional extraction methods.This study aimed to improve the quality of IBT using fresh tea leaves by a two-stage enzymatic processing.The influence of combined enzymatic oxidation and extraction conditions for maximal extractable flavour(taste and aroma)characteristics from fresh tea leaves were investigated.The changes of aroma profiles and chemical constituents including theaflavins(TFs),thearubigins(TRs),theabrownines(TBs)and TRs/TFs ratio in converted tea brews under two-stage enzyme catalyzed fermentation and extraction conditions were further compared between different treatments,based on which the optimised conditions were determined.During the two-stage enzymatic processing,75 kinds of volatile compounds were identified in all processed samples,and the contents of TFs,TRs,TBs and TRs/TFs ratio could be optimized by adjusting different procedures and parameters.The overall properties of final product were compared with two types of commercial IBT.High quality IBT with desired properties and antioxidant activity can be manufactured using fresh tea leaves by two-stage enzymatic processing approach.

基于单宁酶处理原料制备的高茶黄素速溶红茶品质分析

目的研究基于单宁酶发酵加工的红茶原料,制备高茶黄素含量的速溶红茶。方法以速溶红茶中的茶黄素含量为主要评价指标,对红茶原叶和红茶粉碎叶进行两种提取溶剂处理,分析制备得到速溶红茶的感官品质及主要化学成分含量。结果研究发现,用60%乙醇提取红茶粉碎叶制备得到的速溶红茶中,茶黄素含量显著高于水提取工艺,速溶红茶茶黄素含量达到2.3%,是传统红茶原料中茶黄素的3倍,并且速溶红茶得率达到了38%,其感官品质以水提取工艺较佳。结论以高茶黄素茶叶为原料,将其磨成粉,用60%乙醇为提取剂制备的速溶红茶,富含茶黄素。研究结果为速溶红茶的生产加工提供了一定的理论依据,也可以为夏秋茶资源的开发利用提供新方法。

碎绿茶制备速溶茶双螺杆挤压预处理工艺优化

本文以绿茶加工过程中的副产物碎绿茶为原料,经双螺杆挤压预处理后,采用单罐热浸提法制备速溶绿茶。论文重点在考察双螺杆挤压操作参数(机筒温度、螺杆转速、加水量、茶粉喂料量)分别对速溶绿茶品质指标(速溶茶的得率、茶多酚得率、茶多酚含量)影响的基础上,以速溶绿茶的茶多酚得率为主要考察指标,采用4因素3水平的正交试验优化制备速溶绿茶挤压预处理工艺参数。研究结果表明:双螺杆挤压操作参数(机筒温度、螺杆转速、水分添加量、茶粉喂料量)对速溶绿茶品质指标(速溶茶得率、茶多酚得率、茶多酚含量)产生了显著影响;优化的最佳双螺杆挤压操作参数为水分添加量50%、螺杆转速210 r/min、机筒温度95℃、茶粉喂料量11 kg/h,在该条件下生产的速溶绿茶茶多酚得率4.81%,相比未经双螺杆挤压预处理制备的速溶绿茶对照样品得率(2.88%),茶多酚得率提高了1.67倍。研究结果表明采用双螺杆挤压预处理技术制备速溶茶在实际应用中具有较好的发展潜力。

白茶枸杞复合凝胶软糖配方优化及特性评价

研究旨在探讨白茶枸杞复合凝胶软糖的最优配方,并对其特性进行评价。以感官评分为指标,采用单因素和响应曲面试验,研究复合凝胶添加量、速溶白茶粉添加量、枸杞粉添加量、赤藓糖醇添加量对白茶凝胶软糖的感官和物理品质的影响,从而得出最优工艺配方;在此基础上,检测该工艺配方所制软糖的感官品质、物理性质以及抗氧化能力。白茶枸杞复合凝胶软糖的最优工艺配方为复合凝胶(明胶∶卡拉胶=7∶3)添加量15 g,速溶白茶粉添加量0.3 g,枸杞粉添加量1 g,赤藓糖醇添加量13 g、柠檬酸添加量0.1 g。该条件下制得的白茶凝胶软糖感官评分为85.4分,产品色泽均匀,口感协调,兼具白茶和枸杞风味;其物理性状为:弹性0.97±0.01、硬度(1 934.81±69.27) g、咀嚼性1 623.16±171.80;产品的1,1-二苯基-2-苦基肼(DPPH)自由基清除率和总抗氧化能力(T-AOC)分别为(51.86±1.67)%和(0.014±0.002) mmol/g。结果表明优化后的软糖感官色泽、形态、风味、组织均表现较好,物理性状弹性、硬度、咀嚼性较为理想,配方中含白茶和枸杞成分使其具备一定抗氧化能力。本研究可为白茶和枸杞的深度开发和茶在软糖食品方面的应用提供一定的参考。

速溶茶提香保香技术研究进展

香气在速溶茶加工过程中损耗严重,直接限制了其市场发展。而速溶茶的提香保香技术一直是学界、产业界的研究焦点之一。文章就速溶茶原料、加工技术、新设备引入等方面归纳总结前人的提香研究,为速溶茶生产工艺优化和香气提升提供参考。

碎茶末制备速溶绿茶提取工艺研究

为提高碎茶末利用价值,优化速溶绿茶提取工艺,以安康绿茶加工过程中产生的碎茶末为原料,采用超声波提取技术制备速溶绿茶,考察浸提时间、浸提温度、茶水比对速溶绿茶品质及提取率的影响,通过单因素及正交试验确定速溶绿茶的最优提取工艺。结果表明,超声波提取时间20 min,提取温度30℃,茶水比1︰25为最佳提取条件。在此条件下,速溶绿茶得率为24.67%,茶多酚含量为13.78%、游离氨基酸含量为2.30%、咖啡碱含量为3.32%、可溶性糖总量为9.04%。所制得的速溶绿茶干茶色泽嫩绿,汤色黄绿尚亮,滋味醇厚鲜爽,溶解性良好。经优化后的速溶绿茶超声波提取工艺设计合理、稳定可行且重复性高,所制速溶绿茶品质较优。

速溶普洱茶制备过程中香气变化研究

利用气相色谱-质谱联用技术,系统研究了速溶普洱茶制作过程中各个工序的香气物质变化。结果显示,将原料制备成速溶普洱茶,其关键香气物质杂氧化合物的损失率高达96%。其中,原料制成提取液时损失率为40%,提取液制成浓缩液时损失率为70%,浓缩液制成离心液时损失率为8%,离心液干燥制备成速溶普洱茶时损失率高达80%。探索速溶普洱茶不同制作工序对其香气物质的影响,有助于针对性地进行工艺和设备改进,从而改善速溶普洱茶的风味。

黄精速溶茶酶解工艺条件优化及其抗氧化性

为探究黄精速溶茶酶解最佳工艺参数,以黄精速溶茶得率为响应值,以液料比、加酶量、酶解温度和酶解时间4个因素为自变量,通过响应面法进行优化,得到最佳工艺条件。结果表明:黄精速溶茶的最佳工艺条件为液料比21∶1(mL/g)、加酶量1.4%、酶解温度47℃、酶解时间37 min,在此条件下,黄精速溶茶得率为26.08%,与响应面预测值26.82%相近;超声复合酶法浸提的黄精速溶茶色泽呈黄色,黄精多糖含量为3.73%,黄酮含量为0.95%;抗氧化试验表明,黄精速溶茶对1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基和超氧阴离子自由基的IC50分别为14.34 mg/mL和16.45 mg/mL,且其对自由基的清除能力随着其浓度的增加而增大。

连翘叶速溶茶制备及多种功能成分分析

【目的】研究连翘叶速溶茶的制备工艺及功能成分,为连翘资源高附加值利用提供了理论依据和新的方法。【方法】以连翘叶速溶茶得率为指标,对连翘叶水提工艺进行优化;分别以阴干、炒制杀青、杀青发酵的连翘叶为原料,制备连翘叶速溶茶粉FSL-D、FSL-G、FSL-B,并分析其理化性质和功能成分。【结果】1)连翘叶速溶茶的最佳提取工艺为料液比1∶20.14 g·mL^(-1)、提取时间180 min、提取温度90℃,连翘叶速溶茶的平均得率为15.30%。2)FSL-D、FSL-G和FSL-B溶解时间分别为50.04、55.19和46.46 s,均达到了行业标准;FSL-B味道更好且不易结块。功能成分分析表明,3种速溶茶蛋白质含量均在11%以上,总酚含量为3.22%,总黄酮含量为4.44%,总糖含量为47.76%;其中FSLG中连翘脂苷A含量较高,为19.96%。3)连翘叶多糖的抗氧化试验结果表明,多糖分子量越大,抗氧化效果越好;红外光谱结果表明,抗氧化活性与O-H伸缩振动峰、C=O键的伸缩振动峰及-C-H弯曲振动峰活性减弱相关。【结论】以杀青发酵的连翘叶为原料,制备的连翘叶速溶茶(FSL-B)品质较好。

速溶黄大茶辅助降血糖功能及机制研究

目的:探究速溶黄大茶辅助降血糖作用及其机制。方法:将50只大鼠随机分为空白对照组、模型组及速溶黄大茶高、中、低3个剂量组,通过建立地塞米松诱导胰岛素抵抗糖\脂代谢紊乱模型,观察速溶黄大茶对大鼠体质量、空腹血糖值、糖耐量、血清中总胆固醇及甘油三酯含量、胰岛素抵抗指数及α-葡萄糖苷酶活性的影响,初步明确速溶黄大茶辅助降血糖的功能及机制。结果:速溶黄大茶高剂量组对正常大鼠空腹血糖无影响(P>0.05);与空白对照组比较,模型组大鼠体质量下降、糖耐量水平降低(P<0.01)、血清中总胆固醇及甘油三酯水平升高(P<0.01)、胰岛素抵抗指数增加(P<0.01),而对空腹血糖无明显影响(P>0.05);与模型组大鼠比较,速溶黄大茶3个剂量组均能有效增加大鼠体质量、升高糖耐量水平(P<0.01),高剂量组能降低血清中总胆固醇及甘油三酯含量(P<0.01),高、中剂量组能降低胰岛素抵抗指数(P<0.05),同时体外实验显示与阿卡波糖抑制α-葡萄糖苷酶活性相比,速溶黄大茶高、中剂量组差异无统计学意义(P>0.05)。结论:速溶黄大茶具有辅助降血糖作用,其作用机制可能与抑制α-葡萄糖苷酶活性有关。

白芽奇兰速溶茶粉加工过程中香气的变化

以白芽奇兰茶叶制备速溶茶粉为对象,采用感官评价、气相色谱-质谱联用、香气活性值(odor activity value,OAV)等研究速溶茶粉加工过程中的香气变化规律。结果表明,白芽奇兰速溶茶粉加工过程中各阶段样品的整体香气轮廓和香气成分类别具有一定相似性,但在不同加工阶段的香气强度和香气成分含量差异较大;3-乙基-2,5-二甲基吡嗪、脱氢芳樟醇、水杨酸甲酯、藏花醛、香叶醇、吲哚、β-大马士酮、顺式茉莉酮、香叶基丙酮、反式橙花叔醇和茉莉酸甲酯是导致香气变化的关键成分。浸提工艺显著增加了藏花醛、香叶醇、吲哚、β-大马士酮和顺式茉莉酮等成分的OAV,碟式分离、反渗透浓缩和冷冻干燥显著降低了香叶醇、吲哚、β-大马士酮、顺式茉莉酮、茉莉酸甲酯、反式橙花叔醇、3-乙基-2,5-二甲基吡嗪和藏花醛等成分的OAV。超滤除去茶多酚复合物,促进香气成分的释放,导致香叶醇、吲哚、β-大马士酮、顺式茉莉酮和茉莉酸甲酯的OAV增加。本研究阐明白芽奇兰速溶茶粉加工过程中香气成分的变化规律,发现超滤处理促进香气成分的释放,为改良速溶茶粉的加工工艺提高速溶茶粉的香气品质提供理论依据。

高茶黄素速溶红茶的酶促氧化工艺优化及品质分析

为实现夏秋绿茶的高值化利用,本研究以夏秋绿茶为原料,开发一款高茶黄素速溶红茶。在单因素实验的基础上,通过响应面法优化酶促氧化工艺条件,最后对产品的感官评价、理化指标及香气组分进行了分析。结果表明,最优工艺为:酶添加量1/1000(mL/mL),pH4.90,反应温度50℃,反应时间44 min。在该工艺条件下,产品清香可口,汤色橙红透亮,茶黄素含量高达2.11%±0.04%,理化指标均达到相关标准要求。采用顶空固相微萃取(headspace solid-phase microextraction,HS-SPME)结合气质联用(gas chromatography-mass spectrometry,GCMS)法,共检测出70种香气组分,包括醇类16种,酮类15种,醛类6种,酯类9种,酸类5种,酚类4种,碳氢类5种,其他10种。其中醇类相对含量占比最高,高达32.34%±0.14%,整体香气轮廓主要呈现青草香与花香。该研究结果为我国茶叶深加工的发展提供了一定的理论依据。

香茅草固态速溶茶的研制及风味分析

为提高香茅草的开发利用率,最大程度发挥其功效,探讨香茅草固态速溶茶的最佳制备工艺。以香茅草为主要原料,金银花为辅料,以感官评分为考察指标,采用单因素结合响应面优化工艺配方,结合主成分分析(principal component analysis,PCA)、线性判别分析(linear discriminant analysis,LDA)和复合加载分析(composite loading analysis,CLA)对不同浓度的香茅草固态茶电子鼻结果进行风味差异评估。结果表明:香茅草固态速溶粉的最优配方为香茅草添加量700 g、金银花添加量300 g、料液比为1∶15(g/mL)、浸提温度90℃、浸提时间30 min,以及进风口温度175℃、出风口温度80℃,该条件所得香茅草固态速溶茶风味最佳,组织状态稳定,感官评分为92.6。电子鼻结果显示香茅草固态速溶茶风味物质主要是硫化物、氮氧化合物和烷类物质。

速溶茶中试冻干过程模拟研究

目的采用数值模拟方法预测和优化冻干速溶绿茶粉的中试试验生产工艺。方法通过有限元法建立二维传热传质相变模型,模型模拟茶粉冻干过程中温度场、压力场、水分迁移的变化过程。结果利用模型优化的生产工艺为:物料铺盘厚度调整为15mm,采用阶段升温方法,在升华干燥0~2.0h、2.0~4.0h、4.0~6.0 h、6.0~8.0 h及8.0~26.5 h共计5个时间段中,调整环境辐射温度为0、10、30、50、60℃。按上述工艺生产所得的速溶绿茶粉的水分含量(质量分数)是(3.9±0.19)%,各项理化指标符合国家产品标准要求。结论该模型的预测结果与试验结果相吻合,采用数值模拟方法可以用于预测和优化冻干速溶茶粉的中试试验生产工艺,为今后进一步的产业化生产提供参考与借鉴。

红茶谷物冲调粉的配方优化及品质分析

目的:以祁门红茶为功能因子,感官评价为指标,调配优化红茶谷物冲调粉的配方,并对其进行品质分析。方法:采用真空冷冻干燥结合高速粉碎技术处理原料,选取米粉、紫薯、祁门红茶、糙米、黄豆、木糖醇添加量6个指标因素,分别利用单因素试验和响应面分析法,研究复合谷物冲调粉的配方;同时对最优配方的总淀粉、蛋白质、脂肪、灰分、水分含量、冲水温度、冲泡比例进行理化测定。结果:冲调粉的最佳配方为:红茶3.38%、米粉36%、糙米20.92%、木糖醇11%、黄豆9.96%、芡实6%、大豆分离蛋白2.5%、紫薯2.5%、亚麻籽油1%。总淀粉、蛋白质、脂肪、灰分、水分含量分别为39.44%±0.01%、7.60%±0.01%、1.99%±0.17%、1.78%±0.02%、5.80%±0.01%。当粉体粒径100目、冲水温度70℃、冲泡比例1∶5时,粉糊口感最佳,茶香浓郁、色泽亮丽,融合了茶香、谷香与豆香的独特协调风味。结论:该冲调粉与市场同类产品相比,具有低热低脂的优势,同时富含优质蛋白,为开发富含红茶的冲调粉提供参考思路。

超声辅助浸提制备速溶红茶工艺研究

以秋季茶鲜叶为原料,通过单因素及正交试验确定速溶红茶的最优浸提工艺,分析超声波浸提功率、浸提温度、浸提时间对速溶红茶品质及提取率的影响。结果表明:最佳的工艺参数为浸提功率300 W、浸提温度50℃、浸提时间20 min,在此条件下制得的速溶红茶汤色橙红明亮、无沉淀物、香气纯正、滋味醇和纯正,能够快速溶解且溶解均匀,其茶多酚含量为19.06%,咖啡碱含量为9.46%,游离氨基酸含量为6.55%,可溶性糖含量为5.59%,茶黄素含量为1.64%。该方法优化的速溶红茶超声波提取工艺合理、稳定可行、重复性高,所制得的速溶红茶品质较优,可为夏秋茶资源的精深加工与利用提供技术支撑。