共查询到20条相似文献，搜索用时 15 毫秒
1.
利用酵母自溶动力学方程考察了温度、破壁酶、酵母预处理、酵母初始质量分数、盐等理化因素对啤酒酵母自溶过程的影响.温度对酵母自溶速度有很大影响.通过回归分析得到不同体系中反映自溶温度和速度常数关系的Arrhenius方程及相应的自溶反应的活化能Ea;破壁预处理能显著加速酵母自溶,添加破壁复合酶或食盐均有利于加速酵母自溶反应,但两者复合添加有相互抑制作用;酵母初始质量分数对自溶影响不大. 相似文献
2.
Wine was produced from roselle (Hibiscus sabdariffa) calyx extract using strains of Saccharomyces cerevisiae and subjected to physico‐chemical analyses using standard analytical methods. Imported commercial red wine was used as the reference for sensory evaluation. The results showed that ameliorated roselle calyx extract (must) had 4.21% protein, 0.69% titratable acidity, and 21°Brix total soluble solids. The roselle calyx wine had a pH value of 3.43, a titratable acidity of 0.75%, and an alcohol content of 10.8% (w/v), which were all within values for grape wine. Total anthocyanin (TACY) content and total colour density (TCD) of the wine was 22.26 abs/mL and 25.20 abs/mL, respectively. The sensory properties of the roselle wine showed no significant difference with those of the imported red wine and it appears that roselle calyx could be used to produce acceptable coloured wine. 相似文献
3.
4.
Bulent Akbudak 《International Journal of Food Science & Technology》2010,45(2):334-343
This study examines physicochemical changes in newly developed and existing tomato varieties at different levels of maturity. Serum viscosity is an important factor in the selection of tomato varieties for processing. Most of the attributes indicative of quality for fresh and paste tomatoes occurred at a less mature stage and declined with maturity. The canned varieties ‘H9888,’‘H8892’ and ‘H9780’ had a greater ascorbic acid content and antioxidant capacity. The highest lycopene contents were found in the varieties ‘H9888,’‘CXD254,’‘CXD222’ and ‘H9780’. Total soluble solids levels increased with maturity. The highest acidity values occurred in canned ‘Shasta’, ‘CXD254’ and ‘H9780’ varieties. Mid‐ and late‐season varieties harvested at an early stage produced thicker pastes with greater serum viscosity and acidity than tomatoes harvested at other points in the ripening process. The best results were obtained from canned samples of ‘H9888,’‘CXD254’ and ‘H9780.’ 相似文献
5.
该文采用百香果果壳为原料进行果酒发酵生产,通过单因素试验研究原料破碎方式、热处理时间、热处理温度、果胶酶添加量、果胶酶抑制剂种类等因素对百香果果壳发酵果酒中甲醇、乙醇含量的影响。在单因素试验基础上进行正交试验确定最佳条件。结果表明：酿造低甲醇百香果果壳发酵果酒的最佳工艺为原料热处理温度87℃、热处理时间15 min、果胶酶添加量0.17%,在最佳条件下发酵的果酒中甲醇含量为158.11 mg/L,乙醇含量为9.84 mL/100 m L,甲醇含量符合GB/T 15037—2006《葡萄酒》中的规定。 相似文献
6.
Manuel Viuda‐Martos Yolanda Ruiz‐Navajas Juan M. Zaldivar‐Cruz Victor Kuri Juana Fernández‐López Ángel A. Carbonell‐Barrachina JoséÁ. Pérez‐Álvarez 《International Journal of Food Science & Technology》2010,45(6):1111-1118
The aim of this work was to characterise, physico‐chemically, sugar composition and aroma profile of ten honey samples collected by small producers during two seasons and produced in different agricultural ecosystems from Tabasco State (Mexico). The mean values obtained for the physico‐chemical parameters were: pH 3.63; 19.25% moisture; 78.8°Brix sugar; 0.64% ash; 0.25 mS cm?1 electrical conductivity and 0.58 water activity. Based on colour parameters, Tabasco honeys can be placed in the group of dark honeys. In the analysed samples; fructose was the major sugar (39.45%), followed by glucose (35.74%) while sucrose only represented 2.93%. The volatile profiles of the ten honey samples were obtained by gas chromatography‐mass spectrometry. All the honeys were characterised by their high contents of benzene and furan‐related compounds. As a result, artisanal honeys from Tabasco (Mexico) can be considered to present a good level of quality. 相似文献
7.
François Santoni Toussaint Barboni Julien Paolini Jean Costa 《Journal of the science of food and agriculture》2013,93(3):604-610
BACKGROUND: The effect of four cultivation parameters (post‐maturity harvest date, storage period at 0 °C and input of nitrogen or potassium fertilisers) on the physico‐chemical characteristics and composition of volatile compounds in kiwi fruit (Actinidia deliciosa) were evaluated. Five physico‐chemical parameters were selected, namely, pH, total acidity, dry matter, conductivity and refractive index. To our knowledge, no published data are available concerning the influence of nitrogen or potassium fertilisers on the volatile compounds and physico‐chemical parameters in kiwi fruit. RESULTS: Except for total acidity, these parameters were only weakly influenced by cultivation parameters. The concentrations of five main volatile compounds [hexanal, (E)‐hex‐2‐enal, hexan‐2‐ol, ethyl butyrate and hexanol] were also measured using gas chromatography and gas chromatography‐mass spectrometry. This work showed that the total content of volatile compounds decreased with post‐maturity harvest date and storage period of 3 months. In contrast, the input levels of nitrogen and potassium had little effect on the concentrations of volatile components CONCLUSION: This study demonstrates a high degree of difference in the physiochemical parameters and volatile composition of kiwi fruit, depending on the harvest date, the time of storage and the input of fertilisers. © 2012 Society of Chemical Industry 相似文献
8.
9.
该文从猕猴桃中克隆出果胶甲酯酶抑制剂（Pectin Methylesterase Inhibitor,PMEI）基因,经EcoRⅠ/XbaI双酶切后连接到表达载体pPICzαA上,电转化到毕赤酵母GS115筛选出阳性菌株GS115/pPICzαA-PMEI,并将重组酵母表达的PMEI浓缩纯化后应用于果酒发酵。研究结果表明：重组毕赤酵母表达菌株GS115/pPICzαA-PMEI成功构建,PMEI的发酵表达量为35.38 mg/L。将PMEI应用到果酒发酵中,桔子酒甲醇降低47.54%,含量由189.75 mg/L降低到99.55 mg/L;苹果酒甲醇降低21.52%,含量由118.15 mg/L降低到91.20 mg/L;葡萄酒甲醇变化不显著,含量均低于20.00 mg/L,表明PMEI对果胶丰富且内源性果胶酶强的桔子具有明显的降甲醇效果。桔子酒发酵工艺优化的PMEI最低抑制质量浓度8.84 mg/L,最适温度18 ℃,此时桔子酒中的甲醇降低66.40%到89.10 mg/L。这为低甲醇果酒的发酵提供了新的技术路线。 相似文献
10.
对新疆不同成熟度赛买提杏果实发酵的杏果酒理化性质和感官评价进行分析研究。结果表明：不同成熟度赛买提杏果实经酶解后的原果胶、果胶含量及酒精发酵后果酒中还原糖含量、总酸含量、pH 值、色度、色调、甲醇含量均有明显变化。青熟期杏果实经酶解后原果胶含量0.82%、可溶性果胶含量0.27%,发酵后杏果酒甲醇含量271.796 mg/L、酒精度10.57%vol、总酸含量13.6 g/L,酒体颜色呈黄褐色且口感伴有清爽的酸涩。完熟期杏果实经酶解后含原果胶1.04%、可溶性果胶0.55%,发酵后杏果酒甲醇含量为157.69 mg/L、酒精度为12.09%vol、总酸含量为11.98 g/L,酒体口感较为丰富,颜色呈浅金黄色,杏果实风味十足并具有典型性。因此,选择完熟期杏果实酿造的杏果酒有利于发酵过程控制和改善赛买提杏果酒品质。 相似文献
11.
Rosario Baron Manuel Mayen Julieta Merida Manuel Medina 《Journal of the science of food and agriculture》2000,80(2):226-230
White sherry wines were treated with three fining agents (activated charcoal, PVPP and Riduxhigh), in addition to an initial treatment with casein and bentonite, in four different combinations. The wines were stored at 20 or 30 °C for 1 year with a view to examining changes in their flavan‐3‐ol fraction and differences in their degree of sensitivity to browning. Flavan‐3‐ol monomers and dimers, as well as browning measured as absorbance at 420 nm, increased during storage in all the wines. After this period the wines treated with fining agents containing activated charcoal, PVPP and Riduxhigh exhibited less marked browning, with no significant differences among them at both 20 and 30 °C. However, taking into account the higher initial colour of bottled wines treated with Riduxhigh in relation to those treated with activated charcoal or PVPP, this fining agent showed higher capacity to control browning. © 2000 Society of Chemical Industry 相似文献
12.
Ju Shen;Weidong Huang;Yilin You;Jicheng Zhan; 《Comprehensive Reviews in Food Science and Food Safety》2024,23(6):e70048
Methanol is widely existed in fermented fruit wines (FFWs), and the concentration is excessive at times due to inappropriate fermentation conditions. Methanol is neurotoxic, and its metabolites of formaldehyde and formic acid can cause organic lesions and central respiratory system disorders. FFWs with unspecified methanol limits are often produced with reference to grape wine standards (250/400 mg/L). To clarify the causes of methanol production in FFWs and minimize the methanol content, this study summarizes the current process methods commonly applied for methanol reduction in FFWs and proposes novel potential controlling strategies from the perspective of raw materials (pectin, pectinase, and yeast), which are mainly the low esterification modification and removal of pectin, passivation of the pectinase activity, and the gene editing of yeast to target the secretion of pectinases and modulation of the glycine metabolic pathway. The modified raw materials combined with optimized fermentation processes will hopefully be able to improve the current situation of high methanol content in FFWs. Methanol detection technologies have been outlined and combined with machine learning that will potentially guide the production of low-methanol FFWs and the setting of methanol limits for specific FFW. 相似文献
13.
Alice V Mkanda Amanda Minnaar Henriëtte L de Kock 《Journal of the science of food and agriculture》2007,87(15):2868-2879
BACKGROUND: Dry beans (Phaseolus vulgaris) have a range of varieties, colours and sizes. Differences in physicochemical and sensory properties influence consumer choices for beans. This study related consumer preferences to sensory and physico‐chemical properties of selected bean varieties—Jenny, Kranskop, PAN 148, AC Calmont, PAN 150 and Mkuzi—grown in Mpumalanga (MP) and Free State (FS) in South Africa. RESULTS: Significant (P < 0.05) variety, location as well as location × variety interaction effects were found for both physico‐chemical and sensory properties of beans. Jenny‐FS, Mkuzi and PAN 148‐MP beans had relatively long cooking times (>60 min). Some beans (e.g. PAN 150 and Mkuzi beans) were described as bitter, soapy and metallic with a raw‐bean flavour whereas more preferred beans (e.g. Jenny‐MP, Kranskop‐MP) were sweet, soft and with a cooked‐bean flavour. CONCLUSION Apart from small seed size, sensory characteristics such as bitter taste, soapy and metallic mouthfeel and hard texture contributed to consumers' dislike of certain bean varieties. The sweet taste, cooked‐bean flavours, soft and mushy textures of the most accepted varieties seemed to be related to beans with good hydration capacities that facilitated softening during cooking. Copyright © 2007 Society of Chemical Industry 相似文献
14.
15.
José Pires María Letícia Estevinho Xesús Feás Jesús Cantalapiedra Antonio Iglesias 《Journal of the science of food and agriculture》2009,89(11):1862-1870
BACKGROUND: Honey legislation has been addressed to establish the minimum marketing level of the product and the need for consumer protection through correct denominations. Research oriented toward assessment of floral origin and physico‐chemical properties may increase the commercial value of these products. The characteristics of 23 unifloral honeys of Erica sp., from Portugal, were studied. Pollen features and some physicochemical parameters (moisture, ash, pH, free acidity, electrical conductivity, hydroxymethylfurfural content, apparent sucrose, reducing sugars and diastase activity) were determined. RESULTS: All honey samples can be classified as monofloral Erica sp., they gave a mean value of 56% of Erica pollen type. The families Fabaceae and Rosaceae provided the greatest number of pollen types with 8 and 4 pollen types each respectively. The second most important pollen type is Eucalyptus, present in 69.6% of the samples. All honey samples met the international physicochemical quality standards. The present study found a linear correlation (R = 0.996) between the ash content of honeys and their specific conductivity. CONCLUSION: All honey samples can be classified as monofloral Erica sp. Unifloral honeys are increasingly requested and appreciated, despite their higher prices. The samples were found to meet all major international honey specifications. Copyright © 2009 Society of Chemical Industry 相似文献
16.
17.
18.
19.