The effect of sodium chloride content and temperature on pork meat isotherms

The knowledge of sorption isotherms is essential for understanding the drying process. Throughout the dry cured meat process, changes occur in the NaCl content and temperature on the surface of meat products. The aim of this study was to obtain the desorption isotherms from raw and salted meat at different air temperatures and NaCl content. The desorption characteristics were studied in the relative humidity range of 11.2 to 94.5 % at storage temperatures of 5, 13 and 26°C and at 0, 8, 20 and 30% (dm) of added salt (NaCl). The salted meat samples isotherms at 26°C shows a breaking point between water activities (a(w)) of 0.70 and 0.75. At a(w) lower than 0.70, NaCl content and temperature have only a slight effect on water content equilibrium. At a(w) above 0.75, water content equilibrium increased with the increase in NaCl content and the decrease in temperature. A significant NaCl*Temp interaction was detected at a(W) 0.903 and 0.946.     

Effect of moisture content during incubation of soil treated with organic materials on changes in sulphate and sulphide levels

Water-soluble sulphate and total sulphide levels were determined during 0, 3, 6 and 12 weeks' incubation (30°) of soil at varying moisture contents (0–133% mwhc) with and without addition of 1 % organic materials (cellulose, compost and dwarf peas, all in a finely ground state). With added peas, conditions were apparently anaerobic at all moisture contents, since immobilisation of sulphate and accumulation of sulphide occurred. Where cellulose or compost were added, sulphide accumulated only at 80% mwhc and higher moisture contents, and increased with moisture content. In unamended soil and soil + compost only sulphate accumulated at 20–60 % mwhc and accumulation increased with moisture content in this range. Where cellulose was added sulphate immobilisation occurred and was less at 20–60% mwhc than at higher moisture levels. At 80% mwhc or more anaerobic effects were predominent. The optimum moisture contents for the accumulation of sulphate and sulphide were 60% and 133% mwhc respectively.     

The impact of reduced sodium chloride content on Cheddar cheese quality

The effect of varying salt (sodium chloride) addition levels of 0.50%, 1.25%, 1.80%, 2.25%, 2.50% and 3.00% (w/w) on the quality of Cheddar cheese was assessed. Reducing the salt adversely impacted Cheddar flavour and texture. The key compositional parameters of moisture-in-non-fat-substances and salt-in-moisture were most affected. Decreasing salt resulted in a concomitant reduction of pH, a slight reduction in buffering capacity and an increase in water activity and growth of starter and non-starter lactic acid bacteria that resulted in enhanced proteolysis. Lipolysis was not impacted by salt reduction. To produce quality reduced salt Cheddar cheese cognisance must be taken on how to reduce proteolysis, limit growth of NSLAB, reduce water activity, achieve pH 5.0–5.4 by modifications to the cheese making procedure to create a more appropriate environment for selected starter and/or adjunct cultures to generate acceptable Cheddar flavour and texture.     

织物含水率对其湿摩擦性的影响

织物的摩擦性能在一定程度上可以间接地反映其刺痒感和湿黏感。选用4种不同规格的聚酯/棉/麻混纺织物,利用FTT织物触感仪对织物进行动摩擦性能测试,通过调节织物含水率,模拟不同的湿度环境,研究织物在被汗液或雨水浸湿后表面动摩擦因数的变化。结果显示:织物含水率较小时,织物的动摩擦因数随着织物含水率的增加而呈现先增大后减小的趋势,织物刺痒感和湿黏感先增强后减弱;织物经、纬向摩擦性能由于织物密度不同而有所差异;当纱线中聚酯含量一定时,不同混纺比的聚酯/棉/麻织物摩擦性能的差异和规律并不明显。     

食用盐中硫酸根含量品质波动与氯化钠含量品质波动的关系研究

目的探讨食用盐中硫酸根含量品质波动和氯化钠含量品质波动之间的变化关系,从多方面考察食用盐的均匀性。方法选取市场上比较普遍的、具有代表性的不同种类食用盐产品,采用国家标准检验方法,对批量盐产品的硫酸根含量和氯化钠含量进行检测,通过统计方法计算出硫酸根含量的品质波动和氯化钠含量的品质波动。结果发现硫酸根含量的品质波动和氯化钠含量的品质波动这2个参数在表示不同盐产品的均匀性时呈现一致性。结论硫酸根含量的品质波动也可以作为考察盐产品的均匀性的指标,这对抽样检验的代表性和生产过程中品质波动的考察有指导意义。     

关中地区土壤含水率对丝织品老化的影响

为了探究关中地区土壤含水率对丝织品老化影响的规律,采用墓葬土和井水包埋市售桑蚕丝,利用色差仪、显微分析系统、红外光谱仪和万能材料试验机测试了样品老化前后颜色、微观形态、分子结构和抗拉强度的改变,以评价丝织品在包埋环境中的老化状况。结果表明：在20%含水率环境中,丝织品老化最明显;在10%含水率(干燥缺氧)环境中丝织品老化程度最小。在包埋过程中,有粉红色小双孢菌（Microbisporarosea）生成,其分泌物影响丝织品外观。因此,土壤含水率对丝织品老化的影响非常明显。该研究为古代丝织品老化机理和保护研究奠定了基础,对考古现场丝织品的出土保护具有重要意义。     

Modeling the growth of Listeria monocytogenes in cured ready-to-eat processed meat products by manipulation of sodium chloride, sodium diacetate, potassium lactate, and product moisture content

A central composite second-order response surface design was employed to determine the influences of added sodium chloride (0.8 to 3.6%), sodium diacetate (0 to 0.2%), potassium lactate syrup (0.25 to 9.25%), and finished-product moisture (45.5 to 83.5%) on the predicted growth rate of Listeria monocytogenes in cured ready-to-eat (RTE) meat products. Increased amounts of both sodium diacetate (P < 0.11) and potassium lactate (P < 0.001) resulted in significant reductions in the growth rate constants of L monocytogenes. Increased finished-product moisture (P < 0.11) significantly increased growth rate constants. The nfluence of sodium chloride was not statistically significant. The second-order statistical factor for lactate was significant (P < 0.01), but all two-way interactions were not. In general, predicted growth rates exceeded actual growth rates obtained from inoculation studies of four cured RTE meat products (wieners, smoked-cooked ham, light bologna, and cotto salami). The final model will be useful to food technologists in determining formulations that will result in finished cured RTE meat products in which L. monocytogenes is not likely to grow.     

土壤水分对香料烟香味物质和感官质量的影响

盆栽试验条件下,以香料烟品种云香巴斯马1号为材料,研究了土壤水分对香料烟常规化学成分、香味物质及感官质量的影响。结果表明,随土壤水分含量的降低,香料烟总糖、还原糖和挥发碱含量下降,而烟碱和总氮含量以土壤水分55 %±5 %处理最高,40 %±5 %处理次之,70 %±5 %处理最低。随土壤水分含量下降,中部叶(cutters)除新植二烯和乙酰吡咯外,各类香味物质含量以及香味物质总量均呈增加趋势;上部叶类胡萝卜素降解产物、苯丙氨酸降解产物的含量提高,但增幅小于中部叶。上部叶赖百当类物质和西柏烷类物质的含量随土壤水分含量降低而减少,有机酸3项指标和酯类物质含量以土壤水分为50 %±5 %处理最高。评吸结果表明,随土壤水分含量降低,中部叶香气质改善,香气量和浓度增加,杂气和刺激性减小,感官质量变好;上部叶感官质量以土壤水分含量为50 %～60 %处理最好。      

Effect of moisture content on CIE color values in dried apricots

The color change in dried apricots at various moisture contents was studied. Dried apricots originally at 19.32% moisture were first dried to 15.49% and then rehydrated to 20.10%, 25.21% and finally 30.20% moisture levels. The CIE L*, a*, and b* color variables were measured to determine the color of dried apricots, and C* (chroma) and h* (hue) values were calculated from a* and b* values. A linear relationship was found between the color variables and moisture contents at 15.49-30.20%. As the moisture content increased, the L* (lightness), b* (yellowness), C* and h* color values increased while the a* (redness) value decreased for the dried apricots at all moisture levels. Results showed that the moisture content of dried fruits should be specified once the reflectance color variables are reported.     

糙米储藏水分对糊化特性的影响

对13.5%、14.5%、15.5%、16.5%水分条件下储藏的糙米进行定期的RVA测定,糙米放入温度设定为25℃的恒温箱中储藏,储藏时间为6个月,每30d检测一次。结果表明：不同水分储藏样品的峰值粘度随着储藏时间延长不断增加,储藏水分越高,峰值粘度上升越快;水分、时间对峰值粘度影响极显著（p〈0.01）;峰值粘度与储藏时间、水分呈极显著二元线性关系。储藏样品的最低粘度随着储藏时间延长不断增加,水分含量越高最低粘度越高;水分、时间影响极显著;最低粘度与储藏时间、水分呈极显著二元线性关系。不同水分储藏样品的崩解值随着储藏时间延长变化不同;水分、时间影响显著性分别为0.029、0.000;回归方程显示,低水分储藏崩解值随着储藏时间延长而升高,高水分储藏崩解值与时间则成显著一元二次方程的关系。水分、时间对最终粘度影响显著性为0.000;最终粘度随时间、水分变化经曲线拟合呈显著二元线性关系,回归方程显著。储藏期间,糙米回生值随时间延长显著上升,储藏后期趋于下降;方差分析显示时间对回生值影响极显著,水分影响不显著,不同水分样品与储藏时间均呈极显著一元二次方程关系。含水率越高,糙米食味品质保持越好。     

水分含量对鲜湿米粉品质影响

研究不同水分含量对鲜湿米粉成品感官品质,蒸煮特性方面影响;并研究水分含量对鲜湿米粉储藏期内感官品质、微生物指标、蒸煮特性(蒸煮损失率和熟断条率)和酸度影响。结果表明,水分含量为65%鲜湿米粉成品感官评分最高;在储藏期内,随水分含量增加,鲜湿米粉感官品质变劣速度、微生物指标超标、蒸煮损失率和熟断条率及酸度增加也越快。经综合考虑,选鲜湿米粉最宜水分含量为65%。     

Effect of application of ammonium chloride and calcium chloride on alfalfa cation-anion content and yield

A major factor predisposing the cow to periparturient hypocalcemia, or milk fever, is being fed a prepartum ration with a high dietary cation-anion difference (DCAD). The DCAD can be favorably altered to prevent milk fever by decreasing K and Na or increasing Cl and S in forages for cows in late gestation. The objective of this study was to test the hypothesis that application of Cl to alfalfa could increase Cl in forage, thereby lowering DCAD. We conducted a field experiment at 2 Iowa locations in which established plots of alfalfa were treated in April 2001 with 0, 56, 112, or 168 kg of Cl/ha using ammonium chloride, calcium chloride, or a mix of the 2 sources with equal amounts of chloride coming from each source. Plots were harvested 4 times in 2001 and once in 2002 and plant tissue analyzed for mineral composition. Applying chloride from either source once in the spring resulted in increased plant chloride content over all 4 cuttings for that year. Averaged across both locations, chloride levels were elevated from 0.52% in control plots to 0.77, 0.87, and 0.89% Cl in plots treated with 56, 112, and 168 kg of Cl/ha, respectively. Chloride application had no effect on plant potassium, sodium, calcium, magnesium, or phosphorus. These results suggest chloride application can elevate chloride content and lower DCAD values of alfalfa, and also maintain crop yield.     

离子色谱-电导法检测酱油中氯化钠的含量

该研究采用灰化预处理+离子色谱-电导法检测酱油中食盐的含量,并与莫尔法、电位滴定法进行比较。结果表明,莫尔法存在滴定过量问题,电位滴定法对温度等外界环境条件和仪器操作要求苛刻,而离子色谱-电导法具有操作简便快速并具有较好的准确度和精密度。实验结果表明,氯化钠含量处于11.56～11.61 g/100 mL之间,回收率实验结果为96.00%～102.10%,相对标准偏差为0.089%。干扰实验对结果无明显影响,且能同时测定多种离子,可用于成品酱油中氯化钠含量的检验。     

土壤水分对烟苗生长及光合特性的影响

本文用两个烤烟品种为材料进行盆栽试验,研究了土壤水分对种子萌发、烟苗成活及生长的影响。结果表明,随着烟苗逐渐长大,对土壤水分含量的要求逐渐降低。种子萌发最适宜的土壤相对持水量为90%~95%,十字期烟苗成活最适宜的土壤相对持水量为70%~85%;生根期壮苗的特征是根系发达,地上部生长健壮,根/冠比值较大,烟苗含水量适中,最适土壤相对持水量为60%左右;成苗期壮苗的特征是茎秆短粗,叶面积大小适中,叶片较厚,比叶重较大,根系发达,根/冠比值大,叶绿素含量高,净光合速率强,最适土壤相对持水量为60%左右。为培育壮苗,应严格控制烟苗各时期的土壤相对持水量。      

水分对优质稻储藏品质的影响

为改善优质稻储藏入库前含水量,本研究以不同水分梯度(11.5%、12.5%、13.5%、14.5%、15.5%、16.5%)的优质稻为研究对象,通过放入15、20℃进行模拟储藏。研究储藏过程中其整精米率、发芽率、发芽势、脂肪酸值、峰值黏度的变化情况。结果表明:准低温下储藏,含水量为12.5%～14.5%范围内整精米率较好,含水量为14.5%以下,其发芽率、发芽势较好,含水量为12.5%～15.5%都能保证脂肪酸值在较好水平,含水量对稻谷糊化特性影响较显著,含水量较低时峰值黏度较低,含水量升高峰值黏度逐渐升高;准低温以下温度储藏对优质稻整精米率、发芽率、发芽势影响不大,温度越高脂肪酸值、降落数值增加越快,RVA糊化特性受温度影响较大,温度高峰值黏度变化快。     

玉米胚芽水分含量对其油脂品质的影响

研究了玉米胚芽水分含量对其油脂品质的影响。通过调整玉米胚芽中水分含量,提取其中油脂,研究玉米胚芽水分含量变化对其油脂脂肪酸组成、理化指标、主要有益微量伴随物的影响。结果表明:玉米胚芽水分含量变化对其油脂脂肪酸组成和甾醇含量基本没有影响,但随着玉米胚芽水分含量提高,其油脂酸值、过氧化值、色泽都会升高,生育酚含量下降,并且α-生育酚和γ-生育酚含量变化与玉米胚芽油色泽红值具有良好的相关性。     

含水量影响冷冻饺子皮面团力学特性的研究

随着传统文化的升温,人们对非发酵冷冻面团的需求日益增加。研究在确定不同含水量的饺子皮坯冷冻和解冻条件的基础上,重点研究了含水量为46%、48%、50%、52%的面团在冷冻前和历经冷冻、冻藏及室温下自然解冻等工序处理后的硬度、内聚性、拉伸性等力学特性的变化。结果显示:质量为20g直径约为3.5cm的饺子皮坯的在-40℃的条件下,40min后可通过最大冰晶形成带;在-18℃的冻藏条件下,2h后温度基本稳定,室温下的适宜解冻时间为1h。在力学特性方面,含水量48%的面团拉伸性能最好,含水量46%的面团硬度最大,含水量50%的面团冷冻前内聚性最好,含水量为46%的面团冷冻后内聚性最好。     

Effect of gamma-ray irradiation on modeling equilibrium moisture content of wheat

ABSTRACT:  The experimental research found that gamma irradiation dose affected the equilibrium moisture content of wheat at the same relative humidity and temperature of ambient. Values of the equilibrium moisture content decreased with an increasing dose of γ-ray irradiation during both adsorption and desorption. These were due to the changes of wheat starch granules and their water bound ability caused by different irradiation doses. Factor of irradiation dose was added in 3 widely used models for modeling the equilibrium moisture content of irradiated wheat, and the parameters in models were estimated based on the experimental data. Based on the study of correlation coefficient, mean relative error, and standard error the modified Chung–Pfost equation and the modified Henderson equation were found to fit the desorption and adsorption isotherms for wheat, respectively, in the range of experiment at conditions studied.     

水分含量对淡腌大黄鱼贮藏性的影响

以感官、微生物和化学变化为指标,探讨了水分含量对淡腌大黄鱼贮藏性的影响。结果表明,水分含量为60%±1%、55%±1%、50%±2%的样品货架期分别是5、9、11d。3组样品货架期终点时菌落总数(TVC)值约为8lg(cfu/g),总挥发性盐基氮(TVB-N)值约为30mg/100g,硫代巴比妥酸反应物(TBARS)值在贮藏期间均出现峰值。贮藏初期菌相比较单一,共检测到4种细菌,贮藏过程中菌相发生变化,货架期终点时仅残存2种细菌,分别为沃氏葡萄球菌(Staphylococcus warneri)和洛菲不动杆菌(Acinetobacter lwoffii)。