A preliminary study of monosaccharide composition and α‐glucosidase inhibitory effect of polysaccharides from pumpkin (Cucurbita moschata) fruit

In this work, crude polysaccharide extracts were extracted from pumpkin (Cucurbita moschata) fruit by hot water. After removal of proteins and purification, polysaccharides of pumpkin fruit (PP1‐1) were subjected to structural identification. Gas chromatography analysis indicated that PP1‐1 comprised of galactose (86.4%), and glucose (13.6%). The molecular weight of PP1‐1 was measured to be 0.87 × 10⁴ Da by gel permeation chromatography. The inhibitory kinetic evaluation showed that it was non‐competitive inhibition of PP1‐1 on the α‐glucosidase‐catalysed hydrolysis of PNPG. The Michaelis–Menten constant (K_m) was 0.106 m , and the inhibitory constants (K_i), 0.435 mg.     

Effect of air temperature and velocity on moisture diffusivity in relation to physical and sensory quality of dried pumpkin seeds

Understanding the effect of drying process parameters on food quality is helpful in process optimization and control. The objective of this work is to understand the effect of mild and harsh effective moisture diffusivity (D_eff), varied by air temperature and velocity, of drying processes on the physical and sensory quality of flat food products. Pumpkin seeds were selected as a food representative. It was found that increments of air temperature and velocity resulted in increased D_eff and brown color on seed hull surfaces and embryos, but decreased hardness of seed embryos. Changes in taste and aroma of seed embryos were able to be sensed. Indicating that D_eff is related to seed physical quality. Similar phenomena occurred with both tray and fluidized bed drying. Air temperature, velocity, and D_eff should be controlled to ensure the best dried flat food products. Mild drying conditions are potentially preferred for good physical and sensory quality.     

毛细管电泳电化学检测法测定南瓜中糖类物质

高效毛细管电泳-电化学检测同时测定了南瓜中的蔗糖、麦芽糖、葡萄糖、果糖的含量，考察了实验参数对分离、检测的影响。在最佳实验条件下，以125μm直径的铜圆盘电极为检测电极，检测电位为0．7V（vsAg／AgCl），在0．08mol／L NaOH溶液中，上述各组分在13min内完全分离。在0．002～2mmol／L的浓度范围内，蔗糖、麦芽糖、葡萄糖和果糖的线性范围均为0．002～2mmol／L。检出限分别为0．72，1．1，0．48，0．67μmol／L（3倍S／N）。峰电流的相对标准偏差RSD分别为2．15％，4．31％，1．22％和0．24％（n=7，c=0．4mmol／L）。该法直接用于南瓜中蔗糖、麦芽糖、葡萄糖和果糖的测定，结果令人满意。     

杀青条件对酶法提取南瓜果胶影响的研究

探讨了对纤维素酶法提取南瓜果胶效果有影响的两个杀青条件———温度和时间,并研究了优化工艺条件的放大过程。结果表明:杀青温度为85℃,杀青时间为20 min为最佳提取工艺,提取得率为14.3%。在放大15倍的实验中,提取得率为21.4%,这可能是由于放大实验中的测量误差减少所致。实验所得到的最佳果胶提取条件可以为综合利用南瓜提供一定的实验依据。     

南瓜、枸杞、芦荟复合发酵果酒的制造

以南瓜、枸杞、芦荟三种汁液为原料生产复合果酒。通过正交实验筛选出一组最佳的混合汁配方,分别选用三种不同的葡萄酒高活性干酵母菌种、三种不同的接种量,在三种不同的温度下进行发酵,经过正交实验,筛选出一组最佳的复合发酵果酒。实验结果表明,接种0.08%的安琪2号葡萄酒高活性干酵母,控温在23℃下发酵的果酒,营养丰富,色香味俱佳。     

采用超滤技术浓缩提纯南瓜多糖

研究了超滤技术在南瓜多糖浓缩纯化过程中的应用，发现南瓜多糖的最佳超滤条件是：采用截留分子量30KDa的超滤膜，超滤压力为0．100MPa，超滤温度为25℃。在此条件下，截留率达到94．5％，脱色率迭到68．6％，还原糖脱除率达到82．9％。     

低脂化脱水南瓜片生产工艺研究

以南瓜为原料,重点研究了低脂化脱水南瓜片生产过程中切片、烫漂工序对干燥速率和成品品质的影响,探索生产低脂化脱水南瓜片的最佳工艺。     

盐析法从干南瓜皮中提取果胶的技术研究

采用盐析法从干南瓜皮中提取食用果胶，对其制取工艺和条件进行了研究，结果表明：料液比为1：7，萃取液的pH值为2，萃取温度为95℃，萃取时间为90min，并用硫酸铝作沉淀剂，果胶得率达13．6％。与酒精法相比，盐析法提取果胶具有成本底，得率高、果胶制品纯洁等特点。     

南瓜水溶性多糖的含量测定

南瓜干粉样品经甲醇回流脱脂,热水提取、乙醇沉淀,以葡萄糖为对照品,用苯酚-硫酸比色法测定其中水溶性多糖的含量。葡萄糖浓度在20.192～100.960ug/mL范围内,与吸光度呈良好的线性关系,回归方程为:A=﹣0.0012+0.00888C(r=0.9975),测得南瓜中水溶性多糖的含量为(33.74±0.80)%,精密度为1.93%;对照试验的回收率为(99.00±1.57)%,精密度为1.48%。     

气-液-固三相循环流化床蒸发器浓缩南瓜汁

研究了三相循环流化床蒸发器浓缩南瓜汁的传热性能和防、除垢性能 ,分析了主要操作因素对传热性能的影响 ,建立了传热系数经验关联式 ,并且对南瓜汁蒸发浓缩过程进行了质量评估。研究结果表明 ,三相循环流化床蒸发器具有良好的传热性能和防、除垢性能 ,适宜南瓜汁的浓缩 ,在食品工业具有一定的应用前景。