柑橘酒酿造酵母的筛选及特性研究

从柑橘自然发酵液中分离得到的酵母为出发菌,通过初筛及发酵瓶复筛,筛选得酵母菌株GJ-17,该酵母的最适生长温度为28℃,最适pH生长范围为3.2～4.2,耐酒精能力较高,可达到16%Vol.在柑橘汁发酵中发酵能力强,产生酒度较高,残糖较低,产香较好,完全可以作为独立的发酵菌株使用.     

Viscoelastic Properties of Butter

Viscoelastic properties were studied on butters prepared from fractionated high-melting triglyceride (HMT) and anhydrous milk fat (AMF). The elastic moduli (G′), the viscous moduli (G″) and the complex viscosities (η*) were determined as functions of angular frequency (ω). With increasing frequency, η* and G″ decreased while G′ increased. Higher G′, G″ and η* values were obtained for HMT butter, indicative of its firmer characteristics. Shift factors, determined using method of reduced variables, followed the Arrhenius model, from which the energies of activation were calculated. Power law intercepts, determined by relating G* to ω, exhibited a semi-logarithmic inverse relationship with temperature. Slight increase in power law intercepts was observed on storage due to thixotropic rearrangements of fat crystals.     

Stabilization of Anthocyanins of Blood Orange Fruit Juice

The stability of the red color of pigmented orange fruit juice was somewhat improved by pasteurization with microwaves and addition of tartaric acid and gluthathione as mildly acidic and antioxidant agents, respectively. Highest stability was obtained through the formation of complexes between anthocyanins and phenolic compounds, such as rutin and caffeic acid.     

近红外光谱大数据分析塔罗科血橙内在品质的研究

可溶性固形物(total soluble solid,TSS)、可滴定酸(titratable acidity,TA)及维生素C(vitamin C,V_C)含量是评价柑橘内在品质及风味的重要特性指标,应用近红外光谱(near infrared spectrum instrument,NIRS)对塔罗科血橙内在品质进行无损、快速检测。利用近红外光谱(NIRS)收集100个塔罗科血橙样品的300个原始光谱数据,处理得到100个平均光谱,其中随机抽取67个作为校正集,33个作为预测集;运用偏最小二乘法(partial least squares,PLS)建立校正与预测模型,再通过实际验证评价建立的PLS模型的性能;试验得到TSS、TA及V_C预测值与实际值的相关系数r值分别是0.833、0.699、0.925;将PLS模型进行实际验证,TSS的差异基本表现在1%以内,占比71.43%;V_C基本表现在5 mg/100 mL以内,占比70.00%。结果表明NIRS可作为一种快速、无损的方法检测塔罗科血橙的内在品质,但TA的相关系数较差,还有待进一步研究。     

商品柑桔饮料中果汁含量的检测

通过比较不同柑桔原汁和商品柑桔饮料,确定了总酸含量、固糖比、固酸比、总酸与ｐＨ值之比、镁含量、甲醛值和钾含量可用于判断柑桔原汁的真实度;而维生素Ｃ含量和钙含量受其它因素的显著影响而不适宜进行了这种判断。     

高橙果酒降酸技术研究

对高橙果酒的降酸技术进行了研究。试验结果表明，高橙果酒的降酸剂以Na2CO3的使用效果最好，滴定酸为14．01g／L的高橙果酒添加3．0g／L的Na2CO3，果酒滴定酸下降到9．98g／L，不仅改善了口感，还保持了果酒的稳定性。     

橘红果脯的研制工艺

本研究采用响应面法优化了橘红果脯加工工艺。以感官评分、总糖含量为响应值,研究了柠檬酸、氯化钙、糖液质量分数等因素对果脯工艺的影响,并用Box-Behnken响应面法对影响因素进行了优化,采用四因素三水平的响应面分析方法,建立二次多项式回归方程的预测模型,研究各变量交互作用对橘红果脯研制工艺的影响,确定橘红果脯的最佳研制工艺。经响应面法优化橘红果脯的最佳工艺条件为:柠檬酸质量分数0.30%、氯化钙含量0.50%、微波功率210 W、糖液质量分数50%,在此条件下,橘红果脯感官评分为96.85分,总糖含量为46.13%,接近理论值,说明采用响应面法优化所得到的橘红果脯研制工艺参数准确可靠,具有一定的实用价值。     

固相微萃取-气质联用分析塔罗科血橙汁香气成分

采用顶空固相微萃取对塔罗科血橙汁的香气成分进行提取,用气相色谱-质谱对香气化合物进行分析,结合谱库检索技术和保留指数对化合物进行鉴定,应用峰面积归一化法测定各成分的相对含量,共鉴定出39种香气成分,相对总量为87.23%。主要香气成分为烃类(55.13%),酯类(13.67%)、醇类(13.17%)、醛类(4.59%),还有2种酮类(0.67%)。其中相对含量最高的是柠檬烯(50.40%),其次是丁酸乙酯(7.67%)、乙醇(5.38%)、3-羟基己酸乙酯(3.92%)、己醛(3.73%)、芳樟醇(3.32%)、β-月桂烯(1.87%)、α-松油醇(1.50%)、巴伦西亚桔烯(1.50%)、己酸乙酯(1.07%)。     

柚苷酶在柑桔果醋加工中的应用

在柑桔果醋加工中,利用柚苷酶进行脱苦实验,结果表明：发酵温度在25℃-28℃,酸度控制在0．5－0．8 /100mL,柚苷酶加量在15μ/mL,柚苷酶有较佳的活性;酒精度为6．0％－8．0％（V）时,有利于醋酸发酵,制得的果醋清亮透明,酸甜可口,果香明显,基本无苦味。     

柑橘-胡萝卜复合果肉饮料的研制

以柑橘、胡萝卜为主要原料,研制一种新型的复合果肉饮料,重点解决产品配方和悬浮稳定性问题。采用单因素实验和正交试验,产品最佳配方为柑橘浆12.5%、胡萝卜浆12.5%、蔗糖11%、柠檬酸0.15%;稳定剂的最佳组合为羧甲基纤维素(Carboxymethyl Cellulose,CMC)0.25%、黄原胶0.15%。在此配方下,产品口感好,稳定效果佳。     

稻草浆黑液粘弹性初探

应用动态流变仪测定了稻草浆黑液在不同温度(20～60℃),不同浓度(47％～55％)和不同应变频率条件下的储能模量G’、动态粘度η’、耗散角δ。初步分析了稻草浆黑液的粘弹性特征及影响因素,提出了描述粘弹性特征的基本模型,以期为进一步研究其他草类原料(尤其是麦草)制浆黑液的粘弹性特征及对用动态测量方法研究黑液的流变特性提供理论基础和基本方法。     

Viscoelastic Properties of Myofibrillar Protein-Polysaccharide Composite Gels

The influence of polysaccharide gums on thermal gelation of chicken salt-soluble protein (SSP) was studied by determining changes in dynamic: viscoelasticity and aggregation of the protein-gum composites in 0.6M NaCl at pH 6.0. Xanthan gum increased the storage modulus (G') of SSP up to 45°C, but decreased Cl'and inhibited the sol – gel transition at > 45°C. Alginate generally hindered SSP gelation. SSP-gum composite gels cooled to 23°C were weaker but held more water than gels made from SSP alone. Neither gum altered the SSP aggregation pattern, nor the SSP absorption spectra. The inhibition of SSP gelation by both gums appeared mainly due to physical entanglement rather than chemical interactions.     

Viscoelastic Properties of Wiener Sausages During Cooking

Viscoelastic properties of Wieners during cooking were measured by a rheometer using a stress creep procedure (stress of 5 Pas and time of 60 s) for the retardation and the recovery stage. Experiments were performed at 6 temperatures (40–65°C) and 4 times (5–14 minutes). The viscoelastic behavior of Wieners was well described (R² > 0.98) by a Burgers model. Main parameters, the instantaneous compliance J_o; the retardation compliance J₁, the retardation viscosity μ₁ and the Newtonian viscosity μ_o, varied significantly with cooking temperature and time. Four second order regression models were developed for these parameters. Predicted and experimental values were in good agreement (R² > 0.84).     

血橙果实香气成分色谱保留指数预测

应用分子电性距离矢量（MEDV）对血橙中的45种挥发性组分的气相色谱保留指数（RI）进行了定量结构-色谱保留关系（QSRR）研究。通过多元线性回归（MLR）和逐步回归（SMR）得到了该类化合物气相色谱保留指数（RI）的预测模型,模型的复相关系数（R）为0.947,标准误差（SD）为105.039。留一法（Leave-one-out,LOO）交互检验对模型进行了评价,得到的复相关系数（RCV）为0.923,标准误差（SDCV）为126.394。结果表明所建模型具有良好的预测能力和稳定性。      

血橙果酒生产工艺研究

通过研究,确定血橙果酒的生产工艺,为:血橙去皮榨汁后加入0.2 g/L葡萄酒活性干酵母,在24℃发酵5～7 d.糖度降至4%～6%;用4层纱布过滤发酵醪,继续发酵10～14 d后在5～10℃陈酿30 d;加入0.06%壳聚糖,吸附悬浮物72h,膜过滤、包装、灭菌得血橙果酒.血橙果酒为透明的红色、酸度适中、酒体醇厚、香气怡人,总糖(以葡萄糖计)含量48±6.5 g/L,pH4.0±0.52,总酸(以酒石酸计)6±2 g/L.     

脐橙全汁果酒酿造技术研究

以脐橙为原料,对脐橙全汁果酒的酿造工艺进行研究.结果表明,果胶酶用量、SO2添加量、酵母接种量及发酵温度等条件对脐橙果酒品质影响较大;正交实验结果表明,在发酵温度为24℃、SO2用量为80 mg/L、果胶酶用量为50 mg/L、酵母接种量为0.5 g/L的条件下,可制得色泽金黄的优质脐橙全汁果酒.     

Viscoelastic Properties of Xanthan Gels Interacting with Cations

Viscoelastic properties of gels were greatly affected by xanthan gum concentration and types of cations. The storage moduli (G'), measured at 1.0 Hz, were 8.3, 10, and 2700 Pa for xanthan gels at 0.5% polymer concentration and 37, 42, and 13000 Pa for xanthan gels at 1.0% polymer concentration in the presence of Na⁺, Ca²⁺, or Fe³⁺, respectively. The elastic recovery was 27.9, 61.6, and 66.3% for 0.5% xanthan gels, and 38.5, 22.5, and 69.1% for 1.0% xanthan gels, in the presence of Na⁺, Ca²⁺, or Fe³⁺, respectively. The generalized Kelvin model simulated creep compliance and ferric ion was an excellent crosslinker for a rigid, firm gel.     

Viscoelastic Properties of Reduced-fat and Full-fat Cheddar Cheeses

Viscoelastic properties of cheeses with and without 0.2% or 0.5% (w/w) lecithin were studied using oscillatory dynamic experiments and creep tests. Elastic and loss moduli of reduced-fat cheese with lecithin were greater (p < 0.01) than reduced-fat cheese without lecithin, but less (p < 0.01) than these values for full-fat cheese. In creep/recovery tests, the residual strain of full-fat cheese, reduced-fat cheese with 0.5% or 0.2% lecithin, and reduced-fat cheese without lecithin were 7.8, 7.9, 8.1, and 15.4%, respectively. There was good agreement in terms of compliance behavior of the four types of cheese between experimental data and prediction by the generalized Kelvin model with six elements.     

Viscoelastic Effects on the Diffusion Properties of Curdlan Gels

ABSTRACT: The diffusion properties of curdlan gels were characterized against its viscoelastic behavior. With increased junction zones involved in rigid crosslinks in higher concentration gels, the three-dimensional structure of curdlan is characteristic. As the gel concentration increases, the intermolecular crosslinking and apparent viscosity increase, reducing mobility of the polymer chains with slower release rates. The scaling laws confirmed that curdlan gel network structure corresponds to that of polymer chains in a good solvent at the semi-dilute regime. Diffusion of the entrapped agent in 6% gels resembled pseudo-controlled release behavior, and a further increase in gel concentration might produce microspheres that support a sustained release.