适宜口感下的红茶品饮冲泡技术

目的:探究适宜口感下的红茶冲泡上限及其技术参数。方法:以一芽二叶红茶为原料,将感官审评方法制备的茶汤梯度稀释并由50名志愿者品饮,在确定适宜口感浓度的基础上,以适宜口感下水浸出物、茶黄素、茶红素质量浓度为考察指标,优化筛选红茶每次品饮冲泡的技术参数以及适宜口感下的冲泡次数。结果:红茶茶汤中水浸出物、茶黄素、茶红素质量浓度分别为1.40,0.04,0.60 mg/mL时,具有适宜的品饮口感;第1次冲泡采用茶水比(m_茶∶V_水)1∶100 (g/mL)、82℃纯水冲泡4.5 min,第2次冲泡采用茶水比(m_茶∶V_水)1∶50 (g/mL)、86.0℃纯水冲泡3.5 min,两次所得的茶汤均具有适宜的品饮口感并达到适宜口感的水浸出物、茶黄素、茶红素质量浓度;但第3次冲泡采用茶水比(m_茶∶V_水)1∶50 (g/mL)、97.3℃纯水冲泡6.4 min后,所得茶汤口感过淡,同时水浸出物、茶黄素也未能达到适宜口感下的质量浓度要求。结论:适宜口感下的红茶品饮冲泡以冲泡2次...     

4种龟肉酶解液的氨基酸及呈味特性比较

以中华草龟、黄喉拟水龟、中华花龟和鳄龟为原料,分析比较4种龟肉碱性蛋白酶酶解液(分别标记为CEH、MEH、OEH和SEH)在总氨基酸、游离氨基酸和呈味特性上的差异.结果表明:4种龟肉酶解液的总氨基酸和游离氨基酸中均含有16种常见氨基酸.4种酶解液的总氨基酸中含量和百分比最高的氨基酸均为谷氨酸,最低均为蛋氨酸.OEH中总...     

汉中地区泡菜水品质评价

该研究以29份汉中泡菜水为对象,采用电子舌、电子鼻及高效液相色谱（HPLC）和气相色谱-质谱联用（GC-MS）等方法,对汉中地区泡菜水的品质进行了研究。结果发现,汉中地区泡菜水在酸味和后味A等滋味指标以及芳香类物质、烷烃类物质和硫化物等风味指标上的差异相对较大。通过聚类分析（CA）和主成分分析（PCA）发现,汉中泡菜水按其品质可分为三个聚类,其主要差异是由风味所导致的,且隶属于聚类Ⅲ的泡菜水样本在芳香类物质的含量上显著高于其他聚类（P＜0.05）,后味A的强度显著较低（P＜0.05）,其品质要优于其他泡菜水样本。     

酵母抽提物对原酿黄豆酱呈味物质的影响研究

通过自动电位滴定、高效凝胶过滤色谱等方法研究了1%添加量的3款纯品型和3款5'肌苷酸二钠＋5'鸟苷酸二钠（I+G）型酵母抽提物（YE）对原酿黄豆酱中游离氨基酸、5'-呈味核苷酸、小分子肽等呈味物质和感官评价的影响。结果表明,1%添加量的纯品型酵母抽提物YE3、I+G型YE4以及I+G型YE5分别能明显提升原酿黄豆酱的丙氨酸、谷氨酸、5'-呈味核苷酸等鲜味物质的含量,提升效果分别为90%、27%、63倍;纯品型YE2可使分子质量为400～1 000 Da的小分子肽提升64%,并在口感上对应的体现出提鲜、淡咸、抑苦、增厚和协调整体口感等应用效果,应用效果较好的是3款I+G型酵母抽提物。     

添加白酒对人工接种东北酸菜挥发性风味成分及感官特性的影响

该实验研究了添加白酒对人工接种乳酸菌发酵东北酸菜理化、挥发性风味成分及感官特性的影响。首先通过乙醇胁迫及产酸能力测定筛选混菌发酵剂,采用顶空固相微萃取（HS-SPME）结合气相色谱-质谱联用（GC-MS）分析酸菜的挥发性风味成分,并结合感官评分与电子舌鉴定白酒对酸菜感官特性的影响。结果表明,植物乳杆菌（Lactobacillus plantarum）、干酪乳杆菌（Lactobacillus casei）和柠檬明串珠菌（Leuconostoc citreum）3株乳酸菌对乙醇具有一定耐受性且产酸能力较强。添加2%白酒结合3株乳酸菌混菌发酵酸菜的可滴定酸含量较未添加白酒的混菌发酵酸菜降低了4.02%。此外,添加白酒接种发酵酸菜形成了以酯类、酮类、含硫化合物和氨基酸为主的风味结构,并且提高了鲜味,降低了苦涩味,在颜色、味道和口感上均具有显著优势。为实现人工接种东北酸菜的品质提升提供理论基础。     

不同香型、不同风格白酒品评的人格化描述

不同香型、不同风格的白酒,其评语大都是用非量化的形容词或艺术化的语言进行描述。这使品酒员对准确把握、记忆各种香型各种风格白酒特点,评判其优劣造成了困难。本文尝试延伸这种艺术化的评语描述,把不同香型、不同风格的白酒,进行人格化地描述,对解决品酒员的上述困难大有裨益。     

基于生理信号和多元统计的白芽奇兰茶口感评价

目的:调查年轻人对白芽奇兰茶的口感偏好,针对性地对茶饮料进行设计。方法:设计以脑电波(Electroencephalogram, EEG)、皮电活动(Electrodermal activity, EDA)、心率变异性(Heart rate variability, HRV)多元统计分析和感官评价相结合的方法,让24名受试者(其中男女各12人)对7个批次的不同克数和冲泡时长的白芽奇兰茶进行口感偏好评价。结果:EEG的功率谱密度、HRV和EDA的均值能够对受试者的口感偏好进行较准确的预测,均值和喜欢程度呈负相关关系。双因素方差分析表明,HRV和EDA不受被试者男女性别差异和被试茶样本的影响。结论:大部分受试者最喜欢10 g白芽奇兰冲泡10 s的口感。     

Sweet taste receptor expression in ruminant intestine and its activation by artificial sweeteners to regulate glucose absorption

Absorption of glucose from the lumen of the intestine into enterocytes is accomplished by sodium-glucose co-transporter 1 (SGLT1). In the majority of mammalian species, expression (this includes activity) of SGLT1 is upregulated in response to increased dietary monosaccharides. This regulatory pathway is initiated by sensing of luminal sugar by the gut-expressed sweet taste receptor. The objectives of our studies were to determine (1) if the ruminant intestine expresses the sweet taste receptor, which consists of two subunits [taste 1 receptor 2 (T1R2) and 3 (T1R3)], and other key signaling molecules required for SGLT1 upregulation in nonruminant intestines, and (2) whether T1R2-T1R3 sensing of artificial sweeteners induces release of glucagon-like peptide-2 (GLP-2) and enhances SGLT1 expression. We found that the small intestine of sheep and cattle express T1R2, T1R3, G-protein gustducin, and GLP-2 in enteroendocrine L-cells. Maintaining 110-d-old ruminating calves for 60 d on a diet containing a starter concentrate and the artificial sweetener Sucram (consisting of saccharin and neohesperidin dihydrochalcone; Pancosma SA, Geneva, Switzerland) enhances (1) Na⁺-dependent d-glucose uptake by over 3-fold, (2) villus height and crypt depth by 1.4- and 1.2-fold, and (3) maltase- and alkaline phosphatase-specific activity by 1.5-fold compared to calves maintained on the same diet without Sucram. No statistically significant differences were observed for rates of intestinal glucose uptake, villus height, crypt depth, or enzyme activities between 50-d-old milk-fed calves and calves maintained on the same diet containing Sucram. When adult cows were kept on a diet containing 80:20 ryegrass hay-to-concentrate supplemented with Sucram, more than a 7-fold increase in SGLT1 protein abundance was noted. Collectively, the data indicate that inclusion of this artificial sweetener enhances SGLT1 expression and mucosal growth in ruminant animals. Exposure of ruminant sheep intestinal segments to saccharin or neohesperidin dihydrochalcone evokes secretion of GLP-2, the gut hormone known to enhance intestinal glucose absorption and mucosal growth. Artificial sweeteners, such as Sucram, at small concentrations are potent activators of T1R2-T1R3 (600-fold > glucose). This, combined with oral bioavailability of T1R2-T1R3 and the understanding that artificial sweetener-induced receptor activation evokes GLP-2 release (thus leading to increased SGLT1 expression and mucosal growth), make this receptor a suitable target for dietary manipulation.     

Direct and mediated impacts of product and process characteristics on consumers’ choice of organic vs. conventional chicken

There is a lack of research into why consumers value process characteristics. In this study, we test the hypothesis that the impact of process characteristics such as organic and free-range on consumers’ choices of food products is at least partly mediated through expected eating quality or taste expectations. In other words, the process characteristics partly function as cues to (eating) quality. Using a traditional metric conjoint approach based on an additive model, four product characteristics (production method, price, size and information about farmer and rearing conditions) were varied in a fractional factorial conjoint design, creating nine profiles of whole chickens. 384 Respondents rated the nine different chickens in terms of taste expectations and willingness to buy. Since the nine records for each respondent are not independent, we used linear mixed modelling for the mediation analysis. We find that, as expected, taste expectations are a strong predictor of willingness to buy. As hypothesised, the impact of both product and process characteristics on willingness to buy is at least partly mediated through taste expectations. Hence, the study shows that process characteristics are important for consumers, not only in and off themselves, but partly because consumers make inferences about eating quality from knowledge about such process characteristics.     

膜结构体育建筑空间的美学要义

为了实践上的总结把握性和拥有不断创新的意识,对膜结构体育建筑空间的空间审美关系进行了分析,探寻了其空间表现力所在与技术形式的艺术表达张力所在,从而进一步推动结构的发展。