Sulphite binding in ciders

Summary The extent of sulphite binding was measured in commercial ciders, and experimentally observed binding curves were compared with theoretically derived curves based on assessment of the levels of individual sulphite binding compounds determined in the ciders. Subsequently, experimental ciders were fermented under various controlled conditions using nine different strains of cider yeasts. The results indicated considerable differences both in the levels of sulphite binding compounds produced, and in the ability of different yeast strains to produce SO₂ in the cider. Juice concentration and the presence of cloud in juice had little or no effect on sulphite binding. Other factors which affected sulphite binding included the type and condition of juice (especially the effect of pectinase treatment) and, in some instances, the use of added yeast nutrients. Significant sulphite binding was also attributable to unaccountable components, probably derived from poor quality fruit, which were present in the apple juice prior to fermentation.     

O_3处理降解硫藏果蔬原料亚硫酸盐效果的研究

研究了臭氧处理对硫藏杏干、山楂及腌制姜3种果蔬原料中亚硫酸盐的降解效果及影响处理效果的因素。结果表明:经臭氧处理后的硫藏杏干、山楂、腌制姜,其SO2含量明显低于无处理,说明臭氧能有效降解亚硫酸盐;亚硫酸盐的降解率与臭氧通入时间、浸泡溶液pH等因素有关,表现为在一定范围内,随臭氧通入时间、pH的增加而提高;但是,在总浸泡时间和通入臭氧处理时间相同的条件下,浸泡期间内开始通入臭氧处理的时刻对样品最终SO2含量的影响不明显。     

酸法苇浆漂白新工艺的探讨

分析金城造纸股份有限公司生产实际,借鉴国内外应用较广的漂白新技术,对金城造纸股份有限公司漂白工艺的改造,提出OHP和HXP两种工艺路线的改造方案。     

萃取分光光度法测定白砂糖中微量亚硫酸盐

提出了以甲醛溶液作吸收液,分光光度法测定白砂糖中微量亚硫酸盐的新方法。在酸性及过量的Cl-存在下,亚硫酸盐与碘酸钾和盐酸副玫瑰苯胺反应,生成易被异戊醇萃取的稳定的离子缔合物,在λ=560nm处,分光光度法测定。亚硫酸盐(以二氧化硫计)的线性范围为0～50μg,RSD≤3.4%,检出限为2μg。方法简便灵敏,试剂毒性小。结果与国标法相符。     

新闻纸和杂志纸用亚硫酸钠脱墨

目前,脱墨浆在有些纸厂已用作新闻纸配料的重要组分。脱墨浆常用w=70％～85％的旧新闻纸(ONP)和w=15％～30％的旧杂志纸(OMG)     

碱性亚硫酸盐法稻草制浆工艺探讨

本文对碱性亚硫酸盐法稻草浆制浆工艺条件进行了探讨,并与厂家实际使用的生产工艺条件加以比较,从而得出最佳蒸煮工艺条件。     

无硫杏脯褐变控制技术研究

酶促褐变是水果蔬菜加工过程中普遍存在的现象,本文旨在探讨无硫杏脯褐变的最佳控制工艺。采用先单因素后正交试验设计,探讨氯化钙、柠檬酸、氯化钠、D-异抗坏血酸钠及浸泡时间对杏脯多酚氧化酶(PPO)、过氧化物酶(POD)以及色泽的影响。结果显示,无硫杏脯最佳护色工艺配方为氯化钙0.3%+氯化钠1.0%+柠檬酸0.2%+D-异抗坏血酸钠0.2%,浸泡时间4 h,在此条件下可以最大限度的抑制杏PPO、POD活性,保持杏脯色泽。     

稻草亚铵浆的可漂性

对稻草亚铵浆先后进行H、HH、HHP不同漂白条件的尝试 ,结果表明 ,H8H2 P2 三段漂白可将稻草亚铵浆漂至 70 %SBD以上的白度 ,且成纸的主要物理指标均达A级胶印书刊纸标准。     

光叶楮白皮制浆方法的比较及亚铵制浆工艺的优化

采用4种方法对光叶楮白皮制化学浆进行了探讨,并且对光叶楮白皮亚硫酸铵法制浆工艺进行了优化,系统讨论了亚铵用量、尿素用量、蒽醌用量、液比、保温温度和时间对制浆效果的影响,确定出光叶楮白皮亚铵法制浆的最佳工艺条件为:亚铵用量18%,尿素用量5%,AQ用量0.15%,液比1:6,最高温度165℃,保温时间2h.最优化条件下纸浆的粗浆得率为50.3%,细浆得率为48.6%,高锰酸钾值为3.24,白度为51.0%ISO.     

亚硫酸盐在食品加工中的作用及其应用

亚硫酸盐在食品工业中应用已有很长时间,并且使用日益广泛。但随着研究的不断深入,人们发现亚硫酸盐作为食品添加剂在食品安全方面的危害性。本文拟对亚硫酸盐作为食品添加剂在食品加工中的作用、应用方式、安全性、限量及其最新应用进展进行综述。     

影响芦苇中性亚硫酸盐浆次氯酸盐漂白的因素

本文研究了影响中性亚硫酸盐苇浆次氯酸盐漂白的因素，以求达到快速漂白的目的。原浆的硬度高，白度低，次氯酸盐单段漂，难于漂至70％SBD以上的白度；次氯酸盐多段漂，可达到要求的白度，但漂白时间延长；提高温度可加速漂白，但在不加助剂的情况下，不宜超过60℃；提高漂白时的浆浓，可略加快漂白速度，但其主要作用在于节能和减少浆料体积。     

单组分内切葡聚游酶处理提高针叶木亚硫酸盐溶解浆的反应性能

采用单组分内切葡聚糖酶对针叶木亚硫酸盐溶解浆进行处理,探讨了提高溶解浆反应性能的机理。单组分内切葡聚糖酶可在用量相对较低的情况下显著提高用于制备人造丝和纤维素衍生物的溶解浆的反应性能,浆料得率损失较少,纤维素降解程度较低。     

微囊化亚硫酸盐对玫瑰香葡萄贮藏效果的影响

研究以焦亚硫酸钠作为芯材、乙基纤维素和石蜡为壁材制备的微囊保鲜剂对玫瑰香葡萄贮藏效果的影响。结果表明:在0℃贮藏120d后,与对照相比,微囊化亚硫酸保鲜剂处理对葡萄的失重率没有明显影响,腐烂率降低80%以上;与市售保鲜剂相比,漂白率降低35%,腐烂率降低10%,二氧化硫残留量降低20%。     

食品中二氧化硫及亚硫酸盐的作用与检测方法

介绍二氧化硫及亚硫酸盐在食品中的作用、安全性及检测方法。     

The Effect of Low Levels of Sulphite on the Swelling and Solubility of Starches

The effect of low levels of sulphite on the swelling volume and release of polysaccharide from a range of starches pasted at 95°C and 121°C has been investigated. In all cases the addition of 0.01% sulphite enhanced the release of polysaccharide on heating at 95°C and for potato, cassava and sago starches the measured volume showed a marked reduction. In the case of rice and wheat starches, sulphite only had a large effect on the swollen volume at pasting temperatures of 121°C, whereas, even at this temperature, maize was little affected. The addition of the polar antioxidant propyl gallate completely nullified the sulphite effect, with the exception of potato starch, suggesting that sulphite could act by promoting oxidative reductive de-polymerisation of the polysaccharide. The effect of 0.01% sodium chloride was also investigated. It was found to have a similar effect to sulphite in the case of potato starch but did not influence the swelling volume or solubility of the other starches.     

过一硫酸盐羊毛表面改性的红外光谱研究

应用ＦＴＩＲ（ＡＴＲ）分析技术和二次微分谱图处理方法,跟踪分析过一硫酸盐羊毛表面改性技术中的各道工艺对羊毛表面胱氨酸二硫键结构的影响,定性定量地分析胱氨酸的最终氧化产物及其氧化中间产物的形成和变化,并探讨这些氧化成分与羊毛防毡缩性的关系。     

新生亚硫酸钙在糖汁清净过程中的机理

以新生CaSO_3的形貌和结构为出发点,探讨了其在糖汁清净过程中的作用机理。新生CaSO_3絮凝物呈现出疏松多孔的表面结构,对糖汁中悬浮的胶体微粒具有很强的吸附能力。实验数据拟合结果表明,新生CaSO_3对糖汁清净过程符合准二级动力学模型和Temkin吸附等温线。热力学参数显示出CaSO_3的吸附是自发吸热的过程。同时,通过X射线衍射图谱和傅里叶变换红外光谱对絮凝物的成分和结构进行分析,进一步研究了新生CaSO_3在糖汁清净过程中的吸附与包埋机制。     

洗涤对红麻亚硫酸铵浆CEH漂白结果影响的探讨

卡伯值36.5的全秆红麻亚硫酸铵浆采用CEH漂程,在很好的漂间洗涤条件时,漂白浆白度可达84％SBD左右。随着漂间洗涤效率降低,漂白浆白度明显降低,增加漂白药液用量虽仍能使漂白浆获得上述的白度,但浆的聚合度大大降低。其中,C段废液是影响漂白结果的主要因素。     

Capturing of the monoterpene olefin limonene produced in Saccharomyces cerevisiae

Monoterpene olefins such as limonene are plant compounds with applications as flavouring and fragrance agents, as solvents and potentially also in polymer and fuel chemistry. We engineered baker's yeast Saccharomyces cerevisiae to express a (?)‐limonene synthase from Perilla frutescens and a (+)‐limonene synthase from Citrus limon. Both proteins were expressed either with their native plastid targeting signal or in a truncated form in which the plastidial sorting signal was removed. The yeast host strain for expression was AE9 K197G, which expresses a mutant Erg20 enzyme. This enzyme catalyses the formation of geranyl diphosphate, which is the precursor for monoterpenes. Several methods were tested to capture limonene produced by the yeast. Extraction from the culture medium by pentane, or by the addition of CaCl₂ followed by solid‐phase micro‐extraction, did not lead to detectable limonene, indicating that limonene is rapidly lost from the culture medium. Volatile terpenes such as limonene may also be trapped in a dodecane phase added to the medium during fermentation. This method resulted in recovery of 0.028 mg/l (+)‐limonene and 0.060 mg/l (?)‐limonene in strains using the truncated Citrus and Perilla synthases, respectively. Trapping the headspace during culture of the limonene synthase‐expressing strains resulted in higher titres, at 0.12 mg/l (+)‐limonene and 0.49 mg/l (?)‐limonene. These results show that the volatile properties of the olefins produced require specific methods for efficient recovery of these molecules from biotechnological production systems. Gene Bank Nos were: KM015220 (Perilla limonene synthase; this study); AF317695 (Perilla limonene synthase; Yuba et al., 1996 ); AF514287.1 (Citrus limonene synthase; Lucker et al., 2002 ). Copyright © 2014 John Wiley & Sons, Ltd.     

亚铵制浆废液生产有机无机复混肥的工艺及其肥效

以麦草亚铵制浆废液为原料经浓缩固化工艺预处理,预处理后的浓缩液添加有机质和氮、磷、钾以及微量营养元素及调理剂,再经闭路循环流程工艺制成有机无机复混肥.该工艺实现了亚铵制浆废液的再利用,并可清洁化生产有机无机复混肥.