甘蔗一压汁与二压汁的成分差异分析与研究

为了探索糖汁清浊分流澄清新工艺,研究甘蔗压榨中一压汁、二压汁和混合汁的常规成分、无机成分及氨基酸含量的差异。采用甘蔗制糖统一分析方法、电感耦合等离子体发光光谱仪(ICP-AES)、氨基酸分析仪等检测分析方法。结果发现,一压汁的品质优于混合汁,显著优于二压汁。与一压汁相比:混合汁的纯度低1.53 Gp,色值高35.21%(3 358 IU560),无机成分高16.59%,氨基酸含量高19.00%;二压汁纯度低5.22 Gp,色值高60.24%(5 745 IU560),无机成分高58.07%,氨基酸含量高41.11%。蔗汁中的非糖分主要集中在二压汁中。     

香蕉汁生产过程中褐变控制和超滤工艺的研究

采用超滤膜生产澄清香蕉汁,选用膜分子量30000μ的复合膜,超滤膜分离;操作压力为0．7MPa·s时,膜通量达到最大值24．5L／m^2·h。护色工艺试验表明,热烫后加入0．15％半胱氨酸和0．25％柠檬酸,得到的香蕉汁澄清无褐色。     

多孔聚苯乙烯纤维滤膜的形貌结构与过滤性能

采用静电纺丝技术，以四氢呋喃/N,N-二甲基甲酰胺(THF/DMF)为混合溶剂制备多孔聚苯乙烯(PS)微纳米纤维滤膜。系统探讨了PS质量分数、混合溶剂配比及纤维膜厚度对PS微纳米纤维形貌及滤膜过滤效率和过滤阻力的影响。结果表明：随着混合溶剂中THF质量分数的增加，纤维的平均直径逐渐增大，分布在0.8～7.8μm,纤维表面呈现出密集的多孔结构，纤维膜的过滤阻力显著减低。在PS质量分数为15%,THF/DMF溶剂质量配比为90/10,纤维膜厚度为(273±4)μm的条件下，纤维膜对NaCl气溶胶和DOP气溶胶的过滤效率分别为99.08%和96.97%,过滤阻力分别为105.8和116.3 Pa,品质因子分别为0.044 3和0.030 1 Pa^-1,可应用于空气过滤材料领域。     

末效汁汽加热混合汁的初步研究

根据末效汁汽加热混合汁技术在甘蔗糖厂的应用情况,从理论上分析了末效汁汽加热混合汁在甘蔗制糖生产中应用的可行性.     

膜技术在甜菜制糖中的应用

对膜分离技术应用于甜菜制糖工业的渗出汁清净进行了研究。对00.2μm和0.8μm陶瓷膜以及0.1μm不锈钢膜的工艺和及膜的清洗方法进行了试验。结果表明：利用孔径小于1μm或陶瓷膜过滤渗出汁,纯度可以提高2度,确定了膜的清洗方法。     

甘蔗的成熟和收获(六)

第三节甘蔗蔗糖分与混合汁重力纯度的预测预报问:为什么要进行甘蔗蔗糖分和混合汁重力纯度的预测预报?它采用些什么方法?答:糖厂计划科(股)在开榨前编制生产计划,首先要知道原料甘蔗的数量和质量,由于甘蔗的质量(蔗糖分和纯度)对制糖车间的工艺收回指标影响极大,也须首先有了甘蔗蔗糖分和混合汁重力纯度的数据,才便于测算甘蔗产糖率、产糖量和收回率。为此,在开榨前要求在农务科(股)提供第四季度的甘蔗质量     

低温气浮耦合臭氧饱充技术澄清甘蔗混合汁初探

通过低温气浮和臭氧饱充耦合技术,研究了一种甘蔗混合汁绿色清净方法。通过单因素实验和正交实验,分析了臭氧饱充量、反应时间和反应温度对澄清糖汁的影响。结果表明,臭氧饱充量是最为显著的影响因素。实验条件下,较好的澄清条件为:臭氧饱充量0.1%(m臭氧/m蔗汁),反应时间30 min,反应温度为60℃,为混合汁绿色澄清技术的进一步研究提供了基本依据。     

混合汁蔗糠含量及其对澄清过程和糖分收回的影响

讨论了混合汁蔗糠含量对澄清过程和糖分收回的影响。介绍了降低混合汁蔗糠含量的方法。认为,尽力除去混合汁中的蔗糠,对提高甘蔗糖厂的生产能力和糖分收回都有一定的意义。     

ATP荧光微生物快检法中不同材质及孔径微孔滤膜细菌截留效果的评价

在相同的操作条件下考察了直径13 mm的混合纤维素酯膜、聚碳酸酯膜、醋酸纤维素膜、硝酸纤维素膜等4种常用微孔滤膜对细菌的截留能力。以细菌总数含量为10 CFU/m L的水样为待测样品,过滤体积为50m L,过滤测定5次。当孔径为0.22μm时,4种滤膜的平均截留率依次为100%、94%、84%和72%;当孔径为0.45μm时,4种滤膜的平均截留率依次为92%、82%、70%和70%。因此,孔径为0.22μm的混合纤维素酯膜对细菌的截留效果最好。以该滤膜过滤细菌总数含量为42 CFU/m L、20 CFU/m L、10 CFU/m L、4 CFU/m L的水样各50 m L,然后以ATP生物发光法测定膜上细菌,所得ATP荧光值与细菌浓度的线性相关系数R20.9,线性相关性较好。结果显示,0.22μm的混合纤维素酯膜能够满足ATP生物发光法对微菌含量样品的富集测定要求。     

基于不同孔径陶瓷膜处理对泡菜汁品质影响的初步分析

该研究使用不同孔径(0.5,0.2,0.05,0.008μm)陶瓷膜处理泡菜汁,测定不同操作参数下不同孔径陶瓷膜处理泡菜汁微生物截留率、理化指标、有机酸含量、氨基酸含量及风味物质组成,分析了陶瓷膜处理对泡菜汁品质的影响。结果表明,0.008μm孔径膜过滤除菌效果比另外3种好。综合膜通量、理化指标和有机酸含量、氨基酸含量以及挥发性物质组成等多项指标评价,0.05μm孔径陶瓷膜效果最佳。实验确定的最佳过滤条件为:孔径0.05μm,操作压力0.35 MPa,过滤温度40℃,此时膜通量最大,为395 L/(m~2·h),微生物去除率达到99.1%,泡菜汁原有风味损失较低。     

基于红糖生产的蔗汁陶瓷膜过滤工艺技术

采用孔径为8、50 nm及500 nm的陶瓷膜对蔗汁进行过滤澄清生产红糖,解决传统红糖制作利用上浮撇泡方式处理蔗汁清净效果差导致成品糖品质低的问题.对比不同孔径陶瓷膜过滤蔗汁渗透通量大小、清净效果及能耗高低,结合红糖生产工艺需求,得出孔径为50 nm的陶瓷膜最适用于蔗汁过滤澄清生产红糖.在适合的操作条件下,考察孔径为5...     

陶瓷膜在哈密瓜汁微滤除菌工艺中的应用研究

哈密瓜汁对热敏感,为了减少因热处理导致的营养成分和风味物质的损失,采用无机陶瓷膜对哈密瓜汁进行微滤除菌。通过研究三种孔径膜的膜通量、微滤前后哈密瓜汁营养成分的变化及除菌效果,选择最适的膜孔径,并在此基础上选择最适的操作压力和进料温度,从而确定最佳的微滤除菌工艺参数。结果表明:最佳的工艺参数为膜孔径0.2μm,操作压力0.2MPa,进料温度25℃。在此条件下处理的哈密瓜汁透光度可达98.8%,浊度为2.61NTU,菌落总数为13CFU.mL-1,其中大肠菌群、霉菌、酵母菌均未检出。     

Effect of membrane property and operating conditions on phytochemical properties and permeate flux during clarification of pineapple juice

The effects of membrane property on the permeate flux, membrane fouling and quality of clarified pineapple juice were studied. Both microfiltration (membrane pore size of 0.1 and 0.2 μm) and ultrafiltration (membrane molecular weight cut-off (MWCO) of 30 and 100 kDa) membranes were employed. Membrane filtration did not have significant effects on the pH, reducing sugar and acidity of clarified juice whereas the suspended solids and microorganism were completely removed. The 0.2 μm membrane gave the highest permeate flux, total vitamin C content, total phenolic content and antioxidant capacity as well as the highest value of irreversible fouling. Based on these results, the membrane with pore size of 0.2 μm was considered to be the most suitable membrane for the clarification of pineapple juice. The optimum operating conditions for the clarification pineapple juice by membrane filtration was a cross-flow velocity of 3.4 ms⁻¹ and transmembrane pressure (TMP) of 0.7 bar. An average flux of about 37 lm⁻² h⁻¹ was obtained during the microfiltration of pineapple juice under the optimum conditions using batch concentration mode.     

Evaluation of the fouling phenomenon in the membrane clarification of black mulberry juice

Mixed cellulose ester (MCE) flat membranes were used to clarify black mulberry juice, the yield of which was limited by fouling. The effects of membrane pore size (0.025, 0.1 and 0.22 μm), transmembrane pressure (0.5, 1, 1.5 and 200 kPa), and cross‐flow velocity (0.1, 0.2, 0.3 and 0.4 m s^?1) on membrane fouling were evaluated; the results showed that fouling increased with increased pore size and pressure, and decreased with increased velocity. Analysis of different resistances showed that both reversible and irreversible fouling resistances have an important role in fouling‐resistance changes. There is no cake resistance in all processes. Microstructure analysis of membrane using scanning electron microscopy confirmed the theory that intermediate blocking was the dominant fouling mechanism in MCE 0.025 μm, and standard blocking was the dominant mechanism in MCE 0.1 and 0.22 μm.     

Evaluation of hybrid pressure-driven and osmotically-driven membrane process for non-thermal production of apple juice concentrate

This study investigates the potential of hybrid membrane processes including microfiltration (MF), ultrafiltration (UF) and forward osmosis (FO) for non-thermal concentration of apple juice. The process performance and characteristics (physicochemical properties, nutritional and aroma components and microbiological quality) of apple juice were studied. The clarity of apple juice was significantly promoted as pore size of membrane reduced. MF and UF can also ensure microbiological safety in pre-treated apple juice. According to its efficiency of filtration as well as performance of simultaneous clarification and cold-sterilization, 0.22 μm MF membrane was identified as the optimal membrane for the pre-treatment. The pre-treated apple juice can be concentrated up to 65°Brix by subsequent single stage FO. FO retained nutritional and volatile compounds of apple juice while significant reductions were found in the juice concentrated by vacuum evaporation. Hybrid MF-FO can be a promising non-thermal technology to produce apple juice concentrate with high quality.     

微滤膜材质对杨梅汁理化品质及抗氧化活性的影响

为了寻找适合杨梅汁澄清处理的微滤膜,选用聚醚砜膜(PES)、尼龙膜(Nylon)、醋酸纤维膜(CA)、聚偏氟乙烯亲水膜(PVDF)、聚四氟乙烯亲水膜(PTFE)和聚丙烯膜(PP)6种材质的微滤膜,研究不同材质滤膜对杨梅汁理化品质的影响.结果表明:6种材质的滤膜均能有效提高杨梅汁的透光率,降低果汁中蛋白质含量;不同材质滤...     

甘蔗混合汁亚硫酸法澄清过程中Zeta电位的研究

本文系统地研究了混合汁亚硫酸法絮凝澄清过程中Zeta电位的变化规律。在考察氢氧化钙、亚硫酸、磷酸以及絮凝剂等因素对甘蔗混合汁Zeta电位影响的基础上,研究了亚硫酸法工艺中预灰、硫熏中和、絮凝等步骤中混合汁Zeta电位的变化规律。结果表明：甘蔗混合汁Zeta电位的绝对值均随着氢氧化钙、亚硫酸、磷酸以及絮凝剂加入量的增加而减小,当达到最小值后又开始出现增大的趋势;在亚硫酸法絮凝澄清过程中,混合汁Zeta电位的绝对值不断减小,其中,预灰过程中变化较小,硫熏中和过程中降低幅度较大,絮凝过程中缓慢减小到最小值;阳离子聚丙烯酰胺相对于阴离子聚丙烯酰胺絮凝剂,Zeta电位绝对值降低程度更大,絮凝效果更好。本研究结果从Zeta电位的角度较好地揭示了亚硫酸法絮凝澄清过程的本质。     

Clarification of Apple Juice Using Polymeric Ultrafiltration Membranes: a Comparative Evaluation of Membrane Fouling and Juice Quality

The aim of this study was to evaluate the performance of three different commercial polymeric ultrafiltration (UF) membranes during clarification of raw apple juice, comparatively. The influence of membrane pore size, roughness, and hydrophobicity on flux profile and fouling was investigated. The initial flux was simultaneously decreased at the beginning of the process, and quite steady flux was obtained in the membranes with rougher surface and more hydrophobic nature. As the pore size and hydrophobicity increased, the reversible fouling became the major resistance, while cake formation was more prominent for the membranes with narrower pore size. The overall quality results revealed that the main quality characteristics of the raw juice can be better retained by using the membranes that have higher resistance to fouling.     

石榴汁膜除菌工艺研究

以新疆和田酸石榴为原料制作石榴汁,用不同孔径的陶瓷膜对石榴汁进行除菌过滤,对比不同孔径膜的膜通量、除菌效率、成分截留率等参数,确定适于石榴汁膜除菌的膜孔径;并研究了石榴汁陶瓷膜除菌最佳工艺。结果表明,用于石榴汁除菌陶瓷膜的孔径为0.22μm;最佳工艺参数为压力0.20MPa、温度20℃。通过陶瓷膜过滤,可以有效去除石榴汁中的悬浮物和有害微生物,同时保留了其中的营养成分,避免了加热杀菌过程中的褐变、营养成分损失等问题。