成熟温度和时间对Cheddar干酪成熟特性的影响研究

通过对不同成熟参数下Cheddar干酪蛋白分解、质构、pH及感官评价的分析,探讨了成熟参数对Cheddar干酪的影响,并得出研究条件下的最优成熟温度和时间,分析了Cheddar干酪在成熟过程中的游离氨基酸变化情况。     

Accumulation of Some Flavor Compounds in Full- and Reduced-fat Cheddar Cheese Under Different Ripening Conditions

Reduced-fat cheese showed higher levels of ethanol and lower acetoin than full-fat samples throughout ripening regardless of conditions. Total headspace volatiles, as well as butanoic and hexanoic acids, increased with ripening time and temperature. Full- and reduced-fat cheeses developed distinctly different headspace volatile profiles throughout ripening. The effects of ripening conditions were more notable in full-fat samples. Ripening reduced-fat Cheddar cheese at an elevated temperature for a limited time may enhance development of some desirable volatiles such as butanoic acid.     

新疆特色酸凝奶酪成熟过程中产生的非挥发性风味物质研究

非挥发性风味物质对奶酪的口味有重要影响,文中对酸凝奶酪成熟过程中非挥发性风味物质含量的变化进行了研究,结果表明:随着奶酪成熟时间的延长有机酸总量和各种有机酸含量变化差异极显著(P<0.01),主要有机酸乳酸含量最高达到10.75 mg/g;各种游离氨基酸含量处于动态变化过程,总游离氨基酸含量变化显著(P<0.05),缬氨酸和亮氨酸是优势氨基酸,最大含量为35.19 mg/100 g和27.06 mg/100 g;游离脂肪酸总量变化差异极显著(P<0.01)。随着成熟时间的延长,奶酪的营养价值更高,口味更浓郁。     

蓝纹牦牛干酪成熟特性及其风味分析

牦牛乳具有高蛋白、高脂肪的营养特性以及较好的抗疲劳等功能特性。然而,由于牦牛乳产量较低,且产地分散,其在干酪产品开发等精深加工方面研究较少。采用娄地青霉为次级发酵剂,开发蓝纹牦牛干酪,并对其成熟特性以及风味物质进行分析。研究结果显示,娄地青霉能够在牦牛干酪中迅速生长,促进蛋白质的降解并形成大量的多肽、氨基酸等。牦牛干酪成熟末期游离氨基酸,尤其是鲜味氨基酸含量显著升高(P＜0.05)。利用SPME-GC/MS技术在牦牛干酪中共检测出53种风味物质。正交偏最小二乘分析(OPLS-DA)分析显示,与成熟初期相比,蓝纹牦牛干酪风味物质构成在成熟未期发生显著变化,挥发物总含量显著增加(P＜0.05)。牦牛干酪中酯类风味物质主要以脂肪甲酯类为主,且在成熟后期(25、46d)含量相对稳定;脂肪酸类化合物含量在成熟中期最高,但是在成熟末期显著降低(P＜0.05);酮类化合物尤其是甲基酮类,在成熟后期含量显著增加(P＜0.05)。2-壬酮、2-庚酮、辛酸甲酯、2-戊酮、癸酸乙酯、癸酸甲酯、己酸、2-辛酮、丁酸等风味化合物是蓝纹牦牛干酪的主要风味物质。研究表明,娄地青霉能够良好地促进牦牛干酪的成熟,且对牦牛干酪的营养特性以及特征风味的形成具有显著影响。研究结果旨在为我国牦牛乳等特色乳品的深加工奠定理论基础,同时为我国特色乳品产业发展提供参考。     

基于均匀设计的蛋酪蛋坯质构优化方案及风味分析

为开发蛋酪产品,对蛋酪蛋坯的质构及风味进行研究。在单因素试验的基础上,通过均匀设计研究全蛋粉、蛋清粉、卡拉胶、明胶和乳酸菌的添加量及发酵时间对蛋坯质构(硬度、黏性、内聚性、弹性、胶着性和咀嚼性)的影响。结果表明,蛋酪蛋坯质构最佳配方为:全蛋粉添加量5%,蛋清粉添加量5%,卡拉胶添加量0.5%,嗜热链球菌添加量1%,发酵3.5 h。利用GC-O-MS测定最佳质构下的风味物质,共筛选愉悦风味物质10种,不愉悦风味物质5种,中性风味物质4种,愉悦风味占主导地位。     

相对湿度对牦牛毛霉霉菌奶酪成熟过程中品质的影响

为研究不同相对湿度对牦牛霉菌奶酪成熟过程中品质的影响,并确定其在成熟过程中的最佳相对湿度和成熟时间,本实验以牦牛霉菌奶酪为试验材料,将其分别置于相对湿度为30%、50%、70%条件下成熟,测定其在成熟过程中感官品质、质构、pH、营养成分、蛋白质和脂肪分解指标以及挥发性风味物质的变化。结果表明:相对湿度为50%,成熟6 d时,奶酪的感官评分最高且质构较佳。随着成熟时间的延长,三个实验组的水分、蛋白质和脂肪含量呈下降趋势,灰分逐渐上升;pH呈先下降后保持不变或上升。除成熟第0和8 d外,在同一成熟时间点,相对湿度为30%的水分含量均显著低于其他两组(P<0.05);灰分、蛋白质和脂肪含量变化不明显;相对湿度为50%的pH下降速度最快。pH4.6醋酸盐缓冲液可溶性氮含量、12%三氯乙酸可溶性氮含量、酸价和硫代巴比妥酸值均在奶酪成熟过程中不断升高,且相对湿度为50%时值最高。对牦牛毛霉霉菌奶酪挥发性风味物质检测发现,相对湿度为50%,成熟第6 d时,奶酪的风味物质含量较高。因此,牦牛霉菌奶酪在相对湿度为50%,成熟6 d时,其品质最佳。     

杀菌方式对湘西酸鱼挥发性风味物质及质构的影响

采用固相微萃取(SPME)结合气相色谱-质谱联用(GC-MS)技术,研究两种杀菌方式对湘西酸鱼挥发性风味成分的影响,并通过质地剖面测定其对质构特性的影响。结果表明:从湘西酸鱼中共检出87种化合物,主要是酸类(6种)、酯类(33种)、羰基类(22种)、醇类(6种)和碳氢化合物(16种)等。低温杀菌方式形成的风味种类最多,有58种;高温杀菌方式次之,有52种;未处理最差,仅48种。低温杀菌处理有助于挥发性风味物质的形成,而高温杀菌可以最大限度地保持酸鱼固有的感官,其弹性、粘性、咀嚼度优于低温杀菌。     

花生品种对花生酱风味及综合品质的影响

本实验选取7个不同品种的花生制取花生酱,对花生酱中挥发性风味成分的种类和含量进行检测,并结合感官评价、粒径、流变学特性、质构、色度等指标,对比分析花生品种对花生酱风味及综合品质的影响.结果表明,不同品种花生所制取花生酱中挥发性成分的种类和含量有较大差异,7种花生酱中杂环类物质总含量为1.318～9.537?mg/kg,...     

奶豆腐发酵期间挥发性风味组分变化及其感官品质分析

采用固相微萃取结合气相色谱-质谱联用法对实验室自制奶豆腐发酵期间挥发性风味物质进行分析,并对成品奶豆腐与牧民自制奶豆腐的感官品质进行比较。结果表明:发酵期间共检出66种挥发性风味化合物,其中发酵初期(2~4 h)检测到45种,以脂肪酸类物质为主;发酵中期(4~8 h)检测到27种,以醇类、酮类物质为主;发酵后期(8 h~成品)检测到44种,以酮类、芳香族类物质为主。感官评价结果表明实验室自制奶豆腐较牧民自制奶豆腐口感更细腻,奶香味更浓郁;pH 4.6含氮量测定结果也进一步验证了该结论。     

1-甲基环丙烯对李果实采后衰老期间非挥发性风味物质影响的多变量分析

采用多变量分析的方法研究1-甲基环丙烯(1-MCP)对‘黑琥珀’李果实20℃贮藏期间非挥发性风味物质形成的影响。结果表明：李果实中主要的糖酸组分是D-果糖、D-葡萄糖、蔗糖、山梨糖醇和苹果酸,D-果糖在采收时与贮藏前期释放较多,蔗糖在贮藏后期时含量较高;1-MCP处理抑制了蔗糖向D-果糖和D-葡萄糖的转化,延缓了可溶性固形物含量的下降,在贮藏后期,1-MCP处理诱导苹果酸、柠檬酸和L-天冬氨酸含量的降低,而增加了果实的pH值。偏最小二乘回归与通径分析结果表明,感官甜酸比与山梨糖醇、蔗糖呈高度正相关,酸度与苹果酸呈高度正相关,且蔗糖是甜酸比的主效因子,对甜酸比的影响主要是通过对山梨糖醇、D-果糖和苹果酸的间接效应实现的。     

Manufacture and Incorporation of Liposome‐Entrapped Ethylenediaminetetraacetic Acid into Model Miniature Gouda‐Type Cheese and Subsequent Effect on Starter Viability,pH, and Moisture Content

Liposome‐encapsulated ethylenediaminetetraacetic acid (EDTA) was incorporated into a model miniature Gouda‐type cheese (20 g) in order to assess its effect on rennet gelation, starter viability, pH, and moisture content. EDTA was encapsulated within 2 different food‐grade proliposome preparations, Pro‐Lipo Duo and Pro‐Lipo C (50% and 40% unsaturated soybean phospholipids and 50% and 60% aqueous medium, respectively), using the following high‐shear technologies: Ultra‐Turrax (5000 rpm), 2‐stage homogenization (345 bar), or microfluidization (690 bar). Liposome size distribution was affected by the high‐shear technology employed with the proportion of large vesicles (>100 nm) decreasing in the order microfluidization < 2‐stage homogenization < Ultra‐Turrax. All EDTA‐containing liposomes were stable during 28 d refrigerated storage, with no significant (P ≤ 0.05) change in size distribution or EDTA entrapment efficiency (%EE). Liposome composition affected the entrapment of EDTA, with Pro‐Lipo C having a significantly greater %EE than Pro‐Lipo Duo, 63% and 54%, respectively. For this reason, Pro‐Lipo C EDTA liposomes, with and without EDTA, were incorporated into model miniature Gouda‐type cheese. Addition of liposome‐encapsulated EDTA to milk during cheese making did not impact pH or rennet gel formation. No differences in composition or pH were evident in liposome‐treated cheeses. The results of this study show that the incorporation of liposome‐encapsulated EDTA into milk during cheese manufacture did not affect milk fermentation, moisture content, or pH, suggesting that this approach may be suitable for studying the effects of calcium equilibrium on the texture of brine‐salted cheeses.     

不同品种芒果的营养成分及风味物质分析

本论文以产自四川攀枝花地区的四种芒果（大黄芒、大青芒、鹰嘴芒、台芒）为研究对象,通过测定其各项营养成分指标并通过主成分分析 (PCA),结合其挥发性香气成分,对其进行综合评价。结果表明:糖酸比、β-胡萝卜素含量最高的是大黄芒,分别为16.47和4.06 mg/100 g;水分含量、可溶性糖、可滴定酸和总酚含量最高的是鹰嘴芒,分别为82.96%、21.22%、2.03%和0.73 mg/g;可溶性蛋白质含量最高的是台芒,为7.83 mg/g。主成分分析结果表明,芒果评价体系可由两个主成分来表征,综合排名由高到低为鹰嘴芒、台芒、大黄芒、大青芒。四种芒果的挥发性香气成分中,萜烯类化合物占比由高到低分别为大黄芒、鹰嘴芒、台芒、大青芒。本研究为攀枝花芒果产业发展划分提供了一定的理论依据。     

油菜籽品种对浓香菜籽油风味及综合品质的影响

分别以双低油菜籽及传统油菜籽为原料,在相同条件下制取浓香菜籽油,采用溶剂辅助蒸发装置结合气相色谱-质谱联用仪对两种菜籽油中挥发性成分的种类和含量进行测定,并利用偏最小二乘判别分析（partial least squares discriminant analysis,PLS-DA）、气味活度值（odor activity value,OAV）对挥发性成分进行数据分析,确定导致两种菜籽油感官风味差异的关键挥发性风味成分,同时结合感官评价、脂肪酸组成、氨基酸组成、营养成分等指标分析比较两种菜籽油综合品质的差异。结果显示,双低菜籽油及传统菜籽油中分别检出12 类82 种和11 类90 种挥发性成分,总量分别为22 377.88、157 512.98 μg/kg,其中硫苷降解产物总量分别为3 311.07、146 492.82 μg/kg,酚类物质总量分别为12 125.47、4 613.03 μg/kg。利用PLS-DA结合OAV最终确定了13 种最重要的特征风味物质,分别为6-甲基硫基己腈、5-甲硫基戊腈、苯代丙腈、3-丁烯基异硫氰酸酯、苯乙腈、反-2-癸烯醛、正己醇、芳樟醇、乙基苯、苯乙醇、椰子醛、4-乙烯基-2,6-二甲氧基苯酚、3-甲基巴豆腈,其中6-甲基硫基己腈、苯乙腈、芳樟醇、5-甲硫基戊腈、苯代丙腈、3-丁烯基异硫氰酸酯6 种成分均对菜籽油独特的辛辣味具有贡献,且苯乙腈、芳樟醇仅在传统菜籽油中检出;正己醇、苯乙醇、椰子醛则在双低菜籽油中含量更高,对菜籽油的甜味具有重要影响;感官评价表明双低菜籽油的甜味优于传统菜籽油,而传统菜籽油辛辣味更强。双低菜籽油中未检出芥酸,而传统菜籽油中芥酸含量高达30.25%;双低菜籽油中VE和甾醇总含量均高于传统菜籽油。研究结果为不同香型浓香菜籽油的生产提供了原料选择和气味标识的支持。     

一种毛霉表面成熟干酪的蛋白质水解作用评价

从毛豆腐中分离出一株毛霉,并应用于表面成熟干酪,以研究干酪成熟过程中所发生的蛋白质水解作用。在90d 的成熟过程中,干酪的pH 值增加;蛋白质水解作用的评价指标,如干酪外层的水溶性氮- 总氮比、pH4.6水溶性氮- 总氮比、12g/100mL 三氯乙酸可溶性氮- 总氮比,在成熟90d 后分别增加至(23.68 ± 1.07)%、(19.38 ± 1.32)%和(8.61 ± 0.85)%,并且高于干酪的内部相应指标。SDS-PAGE 和毛细管电泳分析干酪的pH4.6 不溶性组分,结果表明酪蛋白在干酪成熟过程中被降解。对干酪成熟过程中分离出的水溶性组分进行RP-HPLC 分析,结果显示成熟过程中蛋白质被水解以及形成一些新肽分子。     

Effect of Hydrocolloid Pre-Treatment on Instrumental and Sensory Texture Attributes of Frozen Carrot (Daucus carota)

The effect of different hydrocolloids (pectin, carboxy methylcellulose, xanthan gum, and sodium alginate) pre-treatment used at different concentrations (0.2–0.4%) on instrumental texture parameters as well as on the sensory attributes of frozen-thawed pre-cut carrots was evaluated. Instrumental texture profile analysis of frozen-thawed carrot showed a significant (P < 0.05) increase in cohesiveness with an increase in the concentration of all the hydrocolloids. Nevertheless, the increase in springiness was not significant (P > 0.05) over the untreated control samples, whereas chewiness did not show consistent results with an increase of any of the hydrocolloids. As the concentration of hydrocolloids increased, the firmness values obtained by cutting the frozen-thawed carrot samples with a Warner Bratzler Blade were also found to increase. Higher texture retention after freezing and thawing was observed in xanthan gum (0.4%) pre-treated samples than other hydrocolloids used as well as than the control samples. It increased the firmness up to 196.2% than the control samples. However, 0.3% xanthan pre-treatment gave the best sensory results. Sensory acceptability increased on increasing the pectin and carboxy methylcellulose concentrations, while lower concentration levels of alginate pre-treatment showed higher sensory preference than the higher concentration levels. Based on the results, untreated frozen samples suffered from a detrimental texture and sensory deterioration during 15 months of frozen storage. The carrot tissue integrity was well retained during frozen storage in the hydrocolloid pre-treated samples.