Comparison of crystallized coconut sugar produced by traditional method and amorphous coconut sugar formed by two drying methods: vacuum drying and spray drying

Coconut sugar is traditionally produced by evaporating sap until reaching its saturated liquid and formed a crystalline structure. This study investigated the comparison of coconut sugar made by traditional method (crystalline structure) and dried coconut sugar (predominantly amorphous structure) to its characteristics. Two different formulation of coconut sap : maltodextrin (7 : 3) and (6 : 4) (weight/weight) were dried using vacuum oven (70℃, 6 hours) and spray dried (Tinlet 120℃.) Coconut sugar was characterized for moisture content, crystallinity, water sorption isotherm, hygroscopic rate, color, dissolving time, and powder recovery. Initial moisture content was examined and in range of 1.33% - 3.44% (wb). The highest monolayer water content was obtained by using spray drying (6 : 4) and lowest was obtained by traditional method. X-ray diffraction showed that dried coconut sugar powder had dominant amorphous structure (70.9 – 71.4%) while traditional one was dominated with crystalline structure (90.5%). Traditional coconut sugar was the least hygroscopic (1.21 × 10-4 g water/g solid/minutes), followed by vacuum dried coconut sugar (1.48 × 10-4 g water/g solid/minutes) and spray dried ones (1.56 – 1.67 × 10-4 g water/g solid/minutes). Spray dried coconut sugar had the brightest and the whitest color, followed by vacuum dried and traditional coconut sugar. Vacuum dried powder was quicker to dissolve (13.33 – 16.67 s), while increasing maltodextrin in spray drying could not decrease the dissolving time. The highest powder recovery of dried sugar was obtained by using vacuum drying and higher maltodextrin concentration (88.70%) while traditional method produced 100% powder recovery.     

碱酶分步法从米粉中提取大米蛋白工艺的研究

用碱法和酶法两步加工米粉,制备大米蛋白.通过研究pH,温度,时间及料液比对大米蛋白提取率的影响,确定稀碱提取大米蛋白的较佳工艺条件为:pH11.0,温度50℃,时间2h,及料液比1:8,然后用碱性蛋白酶对碱提残渣进行二次提取,通过正交试验确定酶提大米蛋白最适条件为:加酶量1%,pH8.0,时间1h,料液比1:8,温度50℃.两步提取使大米蛋白提取率达到90.49%.     

苦荞摊饭法甜型黄酒发酵工艺研究

以苦荞米和糯米(1∶1)为原料,通过单因素及正交试验,得出苦荞摊饭法甜型黄酒的最佳发酵工艺为:酒药用量0.4%,麦曲用量5%,投酒酒度45%vol,投酒量与原料量之比为1∶1(V∶m),发酵温度30℃,主发酵时间11d。该条件下酿造的苦荞甜型酒,经贮存后口味绵软、润滑,色泽黄色、清亮透明、富有光泽,醇香浓郁,具有苦荞甜型黄酒的独特风格。     

密度瓶法测定糯米酒中酒精度的不确定度评定

目的评定密度瓶法测定糯米酒中酒精度的不确定度。方法分析测定过程中不确定度的来源;通过统计方法从测量重复性、温度计读数偏移、密度瓶校准、容量瓶的容量允差和天平校准等方面计算各分量的标准不确定度;最后计算合成不确定度和扩展不确定度。结果当糯米酒的酒精度为13.65%vol时,扩展不确定度U=0.11%vol (k=2)。结论密度瓶法测定糯米酒中酒精度过程中,密度瓶校准的不确定度分量所带来的影响最大,是该方法不确定度的主要来源;其次是是测量重复性;读数偏移、容量允差、天平称量的误差等对其测定不确定度的影响较小。     

氢化物原子荧光法测定大米中总砷含量的不确定度评定

目的 评定氢化物原子荧光法测定大米中总砷含量的不确定度。方法 依据JJF 1059.1—2012《测量不确定度的评定与表示》和CNAS—GL006: 2019《化学分析中不确定度的评估指南》,样品经硝酸-高氯酸-硫酸消解,硫脲-抗坏血酸还原测定总砷含量。同时分析检测过程中的不确定度来源,计算相对标准合成不确定度,最终得到大米中总砷的扩展不确定度。结果 当大米中总砷含量为0.144 mg/kg时,在95%的置信区间下,扩展不确定度为0.012 mg/kg（k=2）。结论 采用氢化物原子荧光法测定时,不确定度的主要来源为样品消解、标准溶液的配制及测量重复性所产生的不确定度。     

响应面法优化超声辅助酶法提取米糠水溶性膳食纤维

以米糠为原料,采用超声辅助酶法提取米糠水溶性膳食纤维,探讨加酶量、超声时间、超声功率和料液比对得率的影响,以水溶性膳食纤维的得率为响应值,通过Box-Behnken实验设计进行超声辅助酶法提取米糠水溶性膳食纤维的工艺优化研究。结果表明:影响米糠水溶性膳食纤维得率的主次因素依次为加酶量、料液比、超声时间、超声功率,最佳提取工艺为酶终浓度5.3%、超声时间5min、超声功率415W、料液比1∶24（g/m L）。在此条件下,米糠水溶性膳食纤维得率最高,预测值为9.22%,验证实验得到的得率为9.36%。      

Effect of fermentation by amylolytic lactic acid bacteria,in process combinations,on characteristics of rice/soybean slurries: A new method for preparing high energy density complementary foods for young children

The use of amylolytic lactic acid bacteria (ALAB) in new methods to prepare high energy density complementary foods for young children was investigated. Using gelatinised slurry, composed of a mixture of rice with soybean, fermentation kinetics by the ALAB Lactobacillus plantarum A6, and chemical and rheological changes were studied at different dry matter (DM) contents. At high DM content (23%), it was possible to obtain a semi-liquid fermented gruel presenting the necessary characteristics to fulfil the energy requirement of young children. Furthermore, combination with spray-drying, as a post-treatment after fermentation by strain A6, had the additional advantage of enabling the use of spray-dried fermented flour to prepare gruels with higher DM content (30–33%) corresponding to 128–140 kcal/100 g of gruel.     

Top-down技术精密度法评定饮用水中氯酸钾含量的不确定度

目的使用Top-down技术精密度法评定饮用水中氯酸盐含量的不确定度。方法按照GB/T5750.10-2006《生活饮用水标准检验方法消毒副产物指标》规定的分析方法,通过对质控样品和能力验证样品的测定,基于Top-down精密度法的原理对数据进行检验和分析。结果通过偏移和精密度核查,在证明分析系统受控的情况下,计算得到不确定的结果U=0.056 mg/L。结论 Top-down技术用于化学分析不确定评估将不确定评估与实验室内部质量控制工作结合,减少了工作量,具有广泛的应用前景。     

响应面法优化黄浆水发酵生产单细胞蛋白的工艺参数研究

以大豆黄浆水为原料,选用白地霉、扣囊拟内孢霉、解脂假丝酵母和产朊假丝酵母（2∶1∶1∶2）作为发酵菌株发酵黄浆水。在单因素试验的基础上,通过响应面设计法,对黄浆水发酵生产单细胞蛋白（SCP）的工艺进行研究。结果表明,影响SCP产量的因素大小顺序为初始pH、发酵时间、装液量;最佳发酵工艺参数为碳氮比5、初始pH 6、装液量140 mL/250 mL、接种量6%、发酵温度28 ℃、发酵时间42 h;经过优化后的SCP产量达到3.28 g/100 mL。     

Top-down线性拟合法评定电感耦合等离子体质谱法测定饮用水中砷含量的不确定度

目的使用Top-down技术线性拟合法评定电感耦合等离子体质谱法测定生活饮用水中砷含量的不确定度。方法按照GB/T 5750.6-2006《生活饮用水标准检验方法金属指标》规定的分析方法,在期间精密度条件下,对不同浓度水平的砷含量进行测定,基于Top-down线性拟合法的原理对积累的数据进行检验和分析。结果在证明建立的经验模型正确后,计算得到不确定的结果U=0.28μg/L。结论 Top-down技术用于化学分析不确定度评估将不确定度评估与实验室内部质量控制工作有机地结合起来,减少了工作量,具有广泛的应用前景。