ADHESION OF SUGAR AND OIL SOLUTIONS

Salt was applied to surfaces coated with sugars and oils to test their adhesion. There was no difference in adhesion between 70% solutions of sucrose, glucose and fructose. Below 70%, adhesion by glucose was greater than for sucrose. Adhesion increased from propylene glycol with two hydroxyl groups to glycerol with three, but there was no change in adhesion from glycerol to sorbitol, which has six hydroxyl groups. The adhesion of glycerol and sorbitol was not different from sucrose. In corn syrups, adhesion increased with increasing dextrose equivalent. Increasing oil content increased adhesion up to 0.2 mg/cm², then plateaued. Oils produced a similar adhesion to solutions of 70% sugar. Adhesion varied with the type of oil. Most likely, the differences in adhesion were due to the presence of natural surfactants. When lecithin was added, the adhesion increased significantly. The addition of other surfactants did not significantly increase the adhesion.

PRACTICAL APPLICATIONS

Sugar and oil are frequently used to adhere powders and small particulates, such as seasonings and spices, to a food surface. The desire for low calorie foods means minimizing the sugar and oil used for adhesion. Glucose was shown to have greater adhesion than sucrose, therefore less of it could be used to achieve the same adhesion. Addition of lecithin to oils increased its adhesion. Certain oils had higher adhesion than others, due to natural surfactants. Most of the fat replacers tested did not show significant adhesion. Using this information, current tack agents could be replaced with other sugars or oils to produce the same adhesion at a lower concentration.     

低糖苦瓜脯渗糖工艺研究

以新鲜苦瓜为原料制作低糖苦瓜脯.通过研究真空度、渗糖温度、渗糖时间、抽真空次数、糖液浓度、冷浸时间对渗糖效果的影响,确定了低糖苦瓜脯真空渗糖的最佳工艺,同时探讨了原料的切分和硬化工艺参数对渗糖效果的影响.结果表明:苦瓜切分为0.7cm～0.8cm环状.20℃饱和氢氧化钙处理2h,填充0.5%的羧甲基纤维素钠,于真空度0.085MPa,60℃下,真空递增渗糖(30%、40%、50%、50%),真空处理4次,每次持续10min,二次渗糖冷浸2h.     

DETERMINATION OF FIRMNESS AND SUGAR CONTENT OF APPLES USING NEAR‐INFRARED DIFFUSE REFLECTANCE1

The objective of this research was to study the potential of near‐infrared (NIR) diffuse reflectance between 800 nm and 1700 nm for determining the firmness and sugar content of apples and to ascertain the effects of apple peel and variety on the NIR prediction of these two quality attributes. The spectral reflectance data were acquired from both peeled and unpeeled ‘Empire', ‘Golden Delicious', and ‘Red Delicious’ apples. Statistical models were developed using principal component analysis/regression. Lower correlations of prediction were obtained (r=0.38 to 0.58) between NIR measurement and Magness‐Taylor firmness for both unpeeled and peeled fruit, with the standard errors of prediction (SEP) between 6.6 N and 10.1 N. Improved predictions were obtained when NIR reflectance was correlated with the slope of the Magness‐Taylor force‐deformation curves. Excellent predictions of the sugar content in peeled apples were obtained (r=0.93 to 0.97; SEP=0.37 to 0.42 °Brix). The SEP, on average, increased by about 0.17 °Brix for the unpeeled apples. Variety did not have a large effect on the model performance on sugar content predictions.     

红外光度法直接测量糖液过饱和度

含有微晶的蔗糖过饱和溶液，随着溶液被加热升温，对光的透射在饱和温度时有最小值，在饱和温度以上，对光的透射迅速上升，峰点所对应的温度即为饱和温度，据此用红外光度法实现糖液过饱和度的直接测量。研究分析了细晶粒度，预结晶作用等因素对测量误差的影响，得到适宜的细晶粒度，细晶用量及分散剂的筛选等实验结果。     

实施糖业标准化促进糖业科技发展

介绍了糖业标准化的概念、意义及其发展.     

CHANGES OF SUGAR PROFILES IN CANNED CLINGSTONE PEACHES

The effect of post-canning storage on sugar profiles in canned clingstone peaches (Primus persica var. ‘Halford’) sweetened with various combinations of sucrose, 62 D. E. corn syrup and 42% high fructose corn syrup was investigated. The sugars in the peach syrups were monitored at 1, 20 and 30° C after storage for 0, 6, 9 and 12 months. The individual sugars in the peach syrups were separated and analyzed by high pressure liquid chromatography (HPLC). Storage of the canned peaches at 30° C resulted in a rapid decrease in sucrose and a simultaneous increase in fructose and glucose. The hydrolysis of sucrose was successively slower at 20 and 1°C. It was observed that the sugar profiles were also dependent on the initial concentration of the sugar components, time of storage and acidity of the canned peaches. The concentration of maltose showed great fluctuation during storage. The rapid loss in quality acceptance of canned clingstone peaches at high storage temperature was explained by the changes in sugar profiles and the accompanying undesirable chemical and physical changes.     

THE THERMAL PROPERTIES OF FROZEN INVERT SUGAR SOLUTIONS

The thermal conductivity, thermal diffusivity, apparent heat capacity and density of frozen invert sugar solutions were found for 40, 50, 60 and 95% sugar inversion, each in concentrations from 2 to 35%, between -40°C and 3.9°C at 2.78°C temperature intervals. The apparatus and instrumentation used was identical with that reported by Keppeler and Boose (1970).     

利用芒果落果加工低糖果脯的研究

初步探讨了以芒果落果制作低糖果脯的加工工艺。结果表明：采用3次真空渗糖工艺，糖液浓度分别为35％、45％、55％，渗糖时间均为30min，并在糖液中添加1．0％的柠檬酸和0．5％的明胶，可得到品质风味优良的低糖芒果果脯。     

FORCE-DEFORMATION AND TEXTURE PROFILE BEHAVIOUR OF AQUEOUS SUGAR GLASSES

Aqueous sugar glasses, simulating the structure of commercial boiled sweets, were investigated in their temperature transition range by force deformation and texture profile tests using the Instron Universal Testing Machine. Cylindrically cast and thermally equilibrated aqueous glucose-sucrose model systems having 2—2.3% moisture (w/w) and containing glucose to sucrose ratios (%w/w) of 100/0, 70/30, 55/45 and 35/65 were used. Force-deformation tests revealed that the Young's modulus was independent of the glucose-sucrose ratio and decreased drastically with temperature from 820 MN/m² at 3°C to 30MJV/m² at 30°C. Texture profile tests were carried out on a model system (35/65 glucose-sucrose blend) and on a commercial hard boiled sweet. Experimental profiles for both systems were largely similar and permitted evaluation of the textural parameters of hardness and cohesiveness. Composite force-strain or force-penetration curves were constructed from series profile tests on the same sample and demonstrated that (a) high values of hardness were found with a flat probe and low temperatures; (b) low values of hardness were found with cone and wedge probes and high temperatures. Cohesiveness generally decreased as the initial applied strain increased, because higher strains resulted in greater sample fracture and/or plastic flow. On the other hand, temperature and probe type had little effect on cohesiveness. The difficulties experienced in bridging the gap between the empirical and the fundamental approaches to texture profiling of food are discussed.     

QUALITY OF FLAVORED YOGURT CONTAINING ADDED COFFEE AND SUGAR

Yogurts flavored with instant coffee (0.5, 0.7 and 0.9%) and sweetened with sugar (4 or 5%) and a control yogurt (no coffee or sugar) were evaluated for chemical, physical, microbiological and sensory properties. The added ingredients generally had no effect on the chemical, physical and microbiological quality of yogurts at day 1 after preparation as compared to the control. During 15 days at 5–7C, pH and lactic acid bacteria counts decreased (P < 0.05) and titratable acidity increased (P < 0.05) in all samples. Yogurts with 0.5% coffee flavoring and 4 and 5% sugar met Turkish Institute Standards for yogurt sensory quality when evaluated by a trained 10‐member panel. Yogurt flavored with 0.5% coffee and containing 5% sugar had most attributes rated in the “like” category by 50% or more of 51 consumer panelists.     

EFFECT OF SUGAR AND GUMS ON THE PASTING PROPERTIES OF CASSAVA STARCH

Pasting properties of cassava starch solutions were prepared with different types of sugars (glucose, sucrose and fructose) at different levels as 10.71, 19.35, 32.43% and gums (gum acacia, guar gum and gum tragacanth) at 0.1, 0.2, 0.3, 0.4% levels, respectively, were analyzed using the Rapid Visco Analyzer. The pasting temperature increased with increase in the sugar concentration in cassava starch–water system and the maximum 78.27C at 32.43% sucrose solution. The peak viscosity (PV) and breakdown viscosity (BD) decreased with increase in the sugar concentration. Hot paste viscosity and cold paste viscosity decreased progressively with increase in sugar concentration in fructose and glucose solution. The PV and BD increased with increase in guar gum concentration and was maximum 5,704 and 3,773 mPa·s at 0.4% concentration, respectively.

PRACTICAL APPLICATIONS

Cassava starch performs most of the functions where maize, rice and wheat starch are currently used. In food industry, cassava starch is used in extruded snacks for improved expansion, as a thickener in foods, in processed baby foods as a filler material and bonding agent in biscuit and confectionary, textile, pharmaceutical, paper and cosmetic industries. Cassava starch can be converted to maltotriose, maltose, and glucose as well as to other modified sugars and organic acids. Starch from cassava can be used to make gelatin capsules. Starches and gums are often used together in food systems to provide texture, control moisture, water mobility, improve overall product quality and stability, reduce cost and facilitate processing. Cassava starch, due to its high swelling power, is reported to yield better quality instant noodles.     

低糖山药脯的加工及相关问题的处理

以新鲜山药为主要原料,研制低糖山药果脯,确定了最佳的工艺流程.结果表明:低糖山药果脯采用浓度为0.1%的CaC12进行硬化处理,在白沙糖液中加入浓度为0.4%的卡拉胶,利用三次渗糖法(20%～35%～46%)工艺进行研制,并提出加工中出现的问题及解决方法.     

EVALUATION OF VARIETAL GRAPE JUICE—INFLUENCE OF PROCESSING METHOD,SUGAR AND ACID ADJUSTMENT,AND CARBONATION1

This study investigated the influence of processing method, sugar and acid adjustment, and carbonation on the quality of grape juice from 5 cultivars of wine grapes. A sensory panel found the juices with adjusted sugar and/or acid rated higher in flavor than the juices with no sugar and/or acid adjustment. Carbonation improved the ratings of the juices with no sugar and/or acid adjustment, but generally had no effect on the adjusted juices. The heat process treatment produced higher color ratings as determined by CDM values in most cultivars. The Riesling and Chelois produced juices that rated comparable to those of Niagara and Concord, the juice industry standards.