影响低温棉籽蛋白KOH蛋白质溶解度因素的研究

使用有机溶剂将棉仁中的棉籽油和棉酚萃取后,余下的棉籽蛋白是一种优良的动物饲料原料。棉籽蛋白KOH蛋白质溶解度的高低直接影响动物对饲料中蛋白质的吸收率。结合生产实际研究了醇、热等变性因素在加工过程中对低温棉籽蛋白KOH蛋白质溶解度的影响,确定了最佳工艺参数,优化了低温棉籽蛋白加工工艺。     

甲醇-乙醇混合溶剂萃取脱酚制备脱酚棉籽蛋白的工艺研究

以脱脂棉籽湿粕为原料,利用甲醇-乙醇混合溶剂萃取脱酚制备脱酚棉籽蛋白,通过单因素试验和正交试验重点探讨了甲醇-乙醇混合比例、混合溶剂体积分数、萃取温度、萃取时间和料液比对脱酚棉籽蛋白游离棉酚含量和蛋白质氢氧化钾溶解度的影响。确定的最佳工艺条件为:甲醇-乙醇混合比例1∶1(质量比),甲醇-乙醇混合溶剂体积分数90%,萃取温度55℃,每次萃取时间25 min,料液比1∶3,分3次进行。在最佳工艺条件下制备的脱酚棉籽蛋白游离棉酚含量为157mg/kg,蛋白质氢氧化钾溶解度为62.7%。     

棉籽仁壳分离系统改造实践北大核心CSCD

棉籽中蛋白质含量丰富,为生产高蛋白质含量棉籽蛋白,对棉籽仁壳分离系统进行改造。通过设计,调整剥壳、筛分、风选系统,对棉籽仁壳分离系统工艺及设备进行优化,得到含壳3%~5%的棉仁过程产品,通过浸出(脱脂脱酚)可得到蛋白质含量为60%~62%的棉籽蛋白产品。该蛋白产品可用于鱼饲料,从而提高棉籽的附加值,促进棉籽加工业的发展。     

脱酚处理对棉籽粕蛋白质消化性的影响研究

为明确脱酚处理对棉籽粕消化性的影响,采用甲醇脱酚处理获得不同游离棉酚含量的棉籽粕,比较了各棉籽粕的蛋白质体外消化性,并进一步以豆粕为对照,比较了市售高温脱酚棉籽粕、市售甲醇脱酚棉籽粕和自制脱酚棉籽粕的蛋白质体内外消化性差异,确定游离棉酚的含量与棉籽粕蛋白质消化性的平衡关系,明确脱酚处理对棉籽粕消化性的影响。结果表明：将高温棉籽粕进行甲醇处理可有效降低其游离棉酚含量(从大于1 000 mg/kg降至500 mg/kg以下),并提高其消化率(从70%升至80%),但并不是游离棉酚含量越低其蛋白质消化性最高。当自制脱酚棉籽粕的游离棉酚含量在689 mg/kg时,其体内外消化率均可达90%以上,而市售甲醇棉籽粕的游离棉酚仅为364 mg/kg,但体内外消化率为82.2%～85.4%。这说明适度的脱酚处理在降低游离棉酚的同时,也有利于蛋白质消化率的提升。由此建议企业在实际的生产中,适度进行脱酚处理(约600～800 mg/kg),既可以有效保障产品的安全性,更可以提升蛋白质的消化性。     

三相萃取法提取棉籽脱酚蛋白的质量分析及安全监控

利用三相萃取法制备棉籽脱酚蛋白,测定其中游离棉酚、蛋白质与纤维含量,以确定棉籽脱酚蛋白质量.并对主要影响因素--游离棉酚含量进行了安全监控:用紫外分光光度法测定其中游离棉酚的含量,用苯胺显色来检测游离棉酚的含量.结果表明,该方法具有简便、重现性好等优点,可作为棉籽脱酚蛋白的安全监控方法.     

低温脱酚棉籽蛋白与普通棉粕和高蛋白棉粕的比较

介绍了低温脱酚棉籽蛋白与普通棉粕、高蛋白棉粕的本质差异,解决了长期以来一直困扰着棉籽加工业、饲料业、养殖业的如何生产和应用低温脱酚棉籽蛋白产品,使企业经济效益、社会效益进一步提升的问题。     

棉籽浓缩蛋白制备及其物理改性工艺研究

以低温脱溶棉籽粕为原料,选用乙醇洗涤法制备棉籽浓缩蛋白。考察了乙醇体积分数,醇洗温度,醇洗时间,醇洗次数,料液比对棉籽浓缩蛋白产品蛋白质含量的影响。得到的最佳工艺条件为:乙醇体积分数70%,醇洗温度50℃,醇洗3次(每次20 min),料液比1∶7;在最佳工艺条件下,制得棉籽浓缩蛋白产品蛋白质含量为68.25%(N×6.25,干基),游离棉酚含量下降到0.035 4%。为提高产品的溶解性,对醇洗棉籽浓缩蛋白进行物理改性研究,探讨了热水温度,捣碎均质时间,蛋白质溶液p H,超声波处理时间对产品溶解性的影响。得到的最佳工艺条件为:热水温度95℃,捣碎均质时间10 min,蛋白质溶液p H 9,超声波处理时间15 min;在最佳工艺条件下,制得的改性棉籽浓缩蛋白产品NSI由12.30%上升到26.59%,且高于原料棉籽粕的24.46%。     

液-液-固三相萃取法提取棉籽脱酚蛋白的质量监控研究

利用液-液-面三相萃取法制备棉籽脱酚蛋白,测定其中游离棉酚、蛋白质与纤维含量．以确定棉籽脱酚蛋白质量。并对主要影响因素——游离棉酚含量进行了质量监控：用紫外分光光度法测定其中游离棉酚的含量,用苯胺显色来检测游离棉酚的含量。结果表明,该方法具有简便、重现性好等优点,可作为棉籽脱酚蛋白中棉酚质量控制方法。     

胰蛋白酶限制性水解脱酚棉籽蛋白的研究

采用胰蛋白酶对脱酚棉籽蛋白进行限制性酶解,以改善棉籽蛋白在中性条件下的溶解性.以酶解棉籽蛋白水解度和溶解度为指标,对胰蛋白酶水解脱酚棉籽蛋白的条件进行了优化.结果表明,胰蛋白酶水解脱酚棉籽蛋白的优化条件为:酶底比2∶ 1(50 000 U/g),底物质量浓度100 g/L,pH 10,于20 ℃下酶解3 h.在此条件下,酶解棉籽蛋白的水解度为10.87%,溶解度为63.48%.与酶解前相比,溶解度提高了43.82%.溶解度分析结果表明,限制性酶解棉籽蛋白在pH 1～11范围内均具有较好的溶解度,仍然保持了棉籽蛋白酸溶性的特点.     

棉仁生坯低温压榨和浸出过程中组分含量的变化

为评估一种脱酚棉籽粕新工艺技术的可行性,对工艺过程中各阶段产品的关键成分(粗蛋白质、游离棉酚、赖氨酸和蛋氨酸等)进行了测定。以脱壳棉仁为原料,经低温压榨和己烷浸出制得脱脂粕,再经甲醇浸出制得脱酚棉籽粕。结果表明,脱酚棉籽粕保留了大部分赖氨酸和蛋氨酸,而粗蛋白质和游离棉酚含量分别为50.15%和0.008 2%;棉仁低温压榨结合己烷及甲醇浸出工艺是一种很有前景的优质脱酚棉籽粕生产技术。     

两种精炼工艺在新疆棉籽油生产加工中的应用对比

阐述了两种精炼工艺(常规精炼工艺和混合油精炼工艺)的工艺流程及控制要点,并将两种工艺生产的成品棉籽油的各项指标进行对比分析。与常规精炼工艺相比,混合油精炼得到的成品棉籽油色泽R值低1.5~2.5,酸值(KOH)低0.08 mg/g,含皂量低0.015个百分点,皂脚含油低10~20个百分点,精炼得率提高2~6个百分点。混合油精炼工艺在新疆棉籽油生产加工中的应用具有精炼得率高、成品油色泽浅、动力消耗低、维护费用低等优势,解决了新疆棉籽高棉酚含量对棉籽油生产加工的不利影响,更适合于新疆棉籽油的加工。     

The effect of roasting nonlinted whole cottonseed on milk production by dairy cows

This study was conducted to examine the effect of roasting nonlinted whole cottonseed on ruminal crude protein (CP) degradability and performance in high-yielding dairy cows. Multiparous Israeli Holstein-Friesian cows (parity average 2.5+/-1.5; n = 132) with 571+/-65 kg of body weight (BW), 107+/-48 d in milk (DIM), and 37+/-5.8 kg of milk yield/d were used in the study. Cows were divided into two dietary treatment groups according to their BW, DIM, and milk production. The two diets were similar in CP, net energy for lactation, and neutral detergent fiber content [17%, 1.74 Mcal/kg, and 30% on a dry matter (DM) basis] and included either 15% (on a DM basis) whole cottonseed or roasted whole cottonseed. Ruminal effective degradability of CP, organic matter (OM), and ether extract (EE) decreased 14, 11, and 10%, respectively, compared to whole cottonseed. Total tract digestibilities of CP and EE were similar for both treatments and averaged 57 and 59%, respectively. However, DM and OM digestibilities were 6 and 5% higher in cows offered roasted whole cottonseed relative to those fed whole cottonseed diet. The inclusion of roasted whole cottonseed in the ration decreased ruminal ammonia and blood urea N concentration by 12% compared with diet with the raw whole cottonseed. Milk production, milk fat content, and production, and milk protein yield increased when roasted, nonlinted whole cottonseed was included in the diet. Milk protein content was similar for both treatments, averaging 2.92%.     

Effect of whole and expanded-expelled cottonseed on milk yield and blood gossypol

Thirty-two primiparous and 12 multiparous Holstein cows were randomly assigned at calving to treatments to determine the effects of type and amount of cottonseed product on plasma gossypol, milk production, and composition, and conjugated linoleic acid concentration in milk fat. Rations consisted of corn silage, corn grain, soybean meal, and cottonseed hulls, and contained on average 16.8% crude protein and 25.3% acid detergent fiber on a dry matter basis. On a dry matter basis, diets contained one of the following: 1) 14% whole cottonseed; 2) 14% expanded-expelled cottonseed; 3) 21% expanded-expelled cottonseed; or 4) 28% expanded-expelled cottonseed. Cows remained on treatment from 30 through 120 d in milk. Dry matter intakes were not significantly different, but intakes of crude protein, acid detergent fiber, and fat were higher for multiparous cows fed whole cottonseed. Multiparous cows fed whole cottonseed had higher yields of milk, fat-corrected milk, crude protein, fat and solids-not-fat than those fed any level of expanded-expelled cottonseed. Concentrations of milk fat, protein, and SNF were not affected by treatment. Although there were treatment differences in fat intake, there were no production differences in primiparous cows. Milk production efficiency (fat-corrected milk/dry matter intake) was not affected by treatment for either multiparous or primiparous cows. Cows fed 14% whole or 14% expanded-expelled cottonseed had similar levels of total plasma gossypol and plasma levels of the negative isomer of gossypol. Increasing the level of expanded-expelled cottonseed in the diet increased both total plasma gossypol and the negative isomer. In this experiment, multiparous but not primiparous cows fed whole cottonseed produced more milk than those fed expanded-expelled cottonseed at 14 to 28% of the diet dry matter, however, feed efficiencies were similar for all treatments.     

整棉仁轧坯萃取制备高蛋白棉粕的工艺研究

以整棉仁为原料,利用油脂浸出工艺,进行破碎、软化、轧坯和萃取得到高蛋白的棉粕。通过单因素实验考察了整棉仁16目筛透过率、软化时间、正己烷萃取次数和正己烷萃取料液比对棉粕质量的影响。结果表明:整棉仁破碎至16目筛透过率10%~20%,在90℃条件下软化60 min,进行溶剂的多次萃取,可得到粗蛋白含量为60%~62%的棉粕。     

浅谈低变性棉籽粕的制备

生产棉籽蛋白的原料棉籽粕在预处理、浸出、脱溶工段与普通的工艺相比有着特殊的要求,从而保证制得的棉籽粕在含杂、蛋白质变性程度、色泽、纤维素含量等方面符合要求。通过生产试验研究了低变性棉籽粕的制备工艺。     

霉变大豆对豆粕质量的影响

大豆霉变后，营养物质含量减少，籽粒变色变味，某些微生物分泌的毒素富集在大豆上可能使籽粒感染上毒素。通过对霉变大豆含量不同的大豆样品和豆粕样品进行油脂含量、粗蛋白含量、氢氧化钾蛋白质溶解度、尿素酶活性、色泽和气味等质量指标的测定，分析和研究霉变大豆对豆粕质量的影响。结果显示，随着霉变大豆含量的增加，豆粕粗蛋白含量有所升高，豆粕氢氧化钾蛋白质溶解度降低，豆粕尿素酶活性降低，豆粕颜色灰暗无光泽，霉变味加重。由此得出。用豆粕蛋白质含量作为评价霉变大豆加工所得豆粕质量的指标是不合适的，而采用豆粕氢氧化钾蛋白质溶解度作为评价指标更为合理。这一结果应在大豆油脂生产和豆粕贸易中受到重视。     

棉籽蛋白资源开发研究进展

我国棉花资源丰富,棉花加工的副产物——棉籽经脱壳提油后的棉籽粕中蛋白质含量高达40%~50%。棉籽蛋白是一种营养价值高、品质良好的植物蛋白资源。介绍了棉籽蛋白的营养价值以及脱酚棉籽蛋白粉、棉籽浓缩蛋白、棉籽分离蛋白等产品的制备工艺及产品的溶解性、持水性、持油性、乳化性与乳化稳定性、起泡性与泡沫稳定性等功能特性的研究进展,并对棉籽蛋白产品目前在食品、饲料、发酵等领域的应用情况进行了论述。     

AN IMPROVED PROCESS FOR ISOLATION OF GLANDLESS COTTONSEED PROTEIN USING INDUSTRIAL MEMBRANE SYSTEMS

An improved process employing a combination of isoelectric precipitation and ultrafiltration to isolate glandless cottonseed protein was developed. The effectiveness of Ca(OH)₂, NaOH, and KOH in extracting storage protein (SP) was compared at pH 10, 9.5 and 9.0. KOH and NaOH each solubilized ca 88% of the flour nitrogen at pH 10, 87% at pH 9.5, and 85% at pH 9.0. Ca(OH), proved less effective, solubilizing about one-fifth as much as the other two hydroxides. Nonstorage protein (NSP) extract was separated by acid precipitation into curd and whey: The lysine-rich NSP whey was then added to SP extract and the mixture ultrafiltered to obtain a higher yield of SP isolate having a lighter color and increased lysine content.     

Texture and Chemical Characteristics of Soy Protein Meat Analog Extruded at High Moisture

The relationships among extruder responses, texture, and protein solubility of soy protein meat analogs were studied. Soy protein isolate and wheat starch at 9:1 ratio were extruded at 60%, 65%, and 70% moisture contents and 137.8, 148.9, and 160°C cooking temperatures. The results showed that moisture content was a more important factor on the overall product texture than cooking temperature. Lower moisture content resulted in higher die pressure, harder texture, and lower total protein solubility. At a fixed moisture content, a higher cooking temperature resulted in a softer and less chewy product but only slightly changed the protein solubility. According to partial least square regression, the data from Texture Profile Analysis, protein solubility, and extruder responses correlated well and could be used to predict each other.