Production and Properties of Spray-dried Amaranthus Betacyanin Pigments

ABSTRACT: Amaranthus betacyanin extracts were spray-dried using a range of maltodextrins [10-25 dextrose equivalent (DE)] and starches (native/modified) as carrier and coating agents at 5 inlet/outlet air temperatures and 4 feed solid contents. Higher inlet/outlet air temperatures caused greater betacyanin loss during spray drying, and affected slightly the pigment stability during storage. Adding maltodextrins and starches significantly reduced the hygroscopicity of the betacyanin extracts and enhanced storage stability. The 25 DE/10 DE mixed powders provided a longer predicted half-life (63.6 wk) compared to the 25 DE and the 10 DE powders separately. The best dried pigment-containing powder made was superior to commercial red beet powder in physical properties.     

Effect of Postharvest Treatments on Amaranthus Betacyanin Degradation Evaluated by Visible/Near-Infrared Spectroscopy

ABSTRACT: A visible/near-infrared spectrophotometric method was developed for betacyanin and moisture content in Amaranthus samples. A standard error of prediction (SEP) of 0.25 mg/g for betacyanins ( r ²= 0.97) and 2.18% for moisture ( r ²= 0.99) was obtained on the validation sample set. Effect of 5 postharvest treatments on betacyanin degradation was assessed. Freeze-drying and -18°C frozen storage gave over 97% pigment retention, compared to natural air (52.8%), solar drying (63.5%), air oven drying (61.9 to 83.1%), and 14°C storage (78.3%). Air-drying gave the lowest degradation rate and longest half-life among the solar and oven-drying treatments for 8 h. Dried samples showed good pigment stability with 28.6 mo half-life at 25°C.     

Modeling Ice Crystal Coarsening in Concentrated Disperse Food Systems

Recrystallization of ice in frozen concentrated aqueous sugar solutions was treated as a diffusion controlled process and has been modeled using a combination of a modified Lifshitz, Slyozov and Wagner theory for coarsening in dispersed phase systems and a mean field theory. The model has been tested using aqueous fructose solutions, water ices and ice creams under a range of time and temperature histories. The model provides data which are in accord with experiments and also suggests that recrystallization cannot be modeled using only diffusion. In certain circumstances other processes must also be considered.     

新型食品胶在冷食中的应用

综述了亚麻籽胶、罗望子胶、酪蛋白酸钠、热凝胶、海藻酸丙二醇酯、微晶纤维素、黄耆胶7种新型食品胶的特性及应用，同时举例说明了复合胶在冷食中的应用。     

Addition of Soluble Soybean Polysaccharides to Dairy Products as a Source of Dietary Fiber

Abstract: Increasing consumption of dietary fiber in food leads to many important health benefits: for example, reduction in blood cholesterol, reduced risk of diabetes, and improved laxation. Water soluble soybean polysaccharide (SSPS) is a dietary fiber extracted and refined from okara, a byproduct of soy manufacturing. It was incorporated into 3 categories of dairy-based products, thickened milkshake-style beverages, puddings, and low-fat ice cream, to the maximum amount without over-texturing the food. Rheological measurements and sensory tests were used to develop desirable SSPS-fortified products. From the rheological data, 4% SSPS-fortified dairy beverages and 4% SSPS -fortified puddings were in the range of commercial products. From sensory analyses, 4% SSPS-fortified dairy beverage with 0.015%κ−carrageenan, 4% SSPS-fortified pudding with 0.1%κ−carrageenan, and 2% SSPS-fortified low-fat ice cream gained the highest scores in consumer hedonic rating. Panelists also indicated their willingness to consume those products if they were available commercially. Practical Application: Since the dietary fiber intake of many people is below their suggested adequate intake values, strategies to successfully fortify foods with fiber may help alleviate this gap. We have developed 3 dairy products, a beverage, a pudding, and a low-fat ice cream, that have been fortified with soluble soybean polysaccharide at levels of 4%, 4%, and 2%, respectively. These products were within acceptable ranges of rheological parameters and other physical stability measurements and were judged to be acceptable by sensory analyses.     

发酵法提取大豆蛋白在食品工业中的应用

探讨了采用乳酸菌发酵法提取大豆蛋白的生产工艺，大豆蛋白质的提取率为８７．４６％，脂肪提取率为７９．１５８％，所获得产品冰淇淋，蛋糕生产中分别最代部分奶粉和鸡蛋，获得较好的替代效果，可望发酵大豆蛋白在食品中有更广阔的应用。     

乳酸链球菌素在食品工业中的应用（三）

本简述了天然食品防腐剂Nisin的四项应用成果。在焙烤食品,冰淇淋中应用,可以抑制蜡状芽孢杆菌,李斯特氏菌的生长,防止食物中毒。在果汁饮料中的应用,可以防止因酸土芽孢杆菌的污染而引起果汁饮料的酸败。在葡萄酒酿造中的应用,可以抑制苹果酸－乳酸发酵。     

Epoxy and cyclopropenoid fatty acids in Amaranthus paniculatus seed oil

Amaranthus paniculatus (L) syn Amaranthus caudatus, (L) seed oil contains palmitic (19-4%), stearic (3-9%), oleic (21-9%), linoleic (43-9%), vernolic (7-8%), malvalic (1-5%) and sterculic (1-6%) acids. These fatty acids were characterised by IR, NMR, MS and GLC techniques and by chemical degradations.     

Recrystallization in Model Ice Cream Solutions as Affected by Stabilizer Concentration

Ice recrystallization rates in simple aqueous solutions comprising fructose and a hydrocolloid stabilizer were measured. The stabilizers were an enzyme-modified guar and a non-gelling high methoxy pectin. The stabilizer concentration dependence of the recrystallization rates for both materials was similar in that increasing the concentration resulted in decreasing rates until a point is reached where further addition had no additional effect. That recrystallization rates were reduced by both gelling and non-gelling stabilizers was strongly suggestive that gelation was not a requirement for recrystallization inhibition and another more specific mechanism applies, for example a weak interfacial effect such as adsorption or blocking. This behavior was also seen with locust bean gum and guar and provided further empirical evidence to support the hypothesis that stabilizers adsorb to ice crystal surfaces.     

结晶原理和冰淇淋中的结晶现象

阐述了结晶原理在冰淇淋凝冻中的应用,详细叙述了结晶的目的和方法,晶核的形成原理,结晶体的成长,多晶现象,以及冰淇淋中的结晶现象.     

GPC-GC-MS法测定冰淇淋、果冻中的塑化剂

建立了冰淇淋、果冻中4种邻苯二甲酸酯的凝胶渗透色谱-气相色谱-质谱(GPC-GC-MS)测定方法,并对结果产生原因进行了分析.样品用乙酸乙酯提取,经GPC净化浓缩后,用GC-MS测定.采用HP-5毛细管管柱分离,定性离子丰度比定性,外标法定量离子定量.方法检出限0.1mg/kg,平均加标回收率92.0％～105.0％,相对标准偏差0.89％～3.14％.     

棕榈油中间分提物(PMF)在冰淇淋中应用研究

通过对棕榈油中间分提物(PMF)理化性质分析,表明棕榈油中间分提物理化性质能满足生产冰淇淋要求,并用此特定油脂进行冰淇淋配方研究,确定PMF油基冰淇淋最佳配方:PMF添加量为6%、脱脂乳粉添加量为8%、糖添加量为13%、乳化剂添加量为0.5%、稳定剂添加量为0.2%。     

The use of spinning disc reactor for processing ice cream base – effect of ageing in making model ice cream

Spinning disc reactor (SDR) technology was tested to produce an ice cream base, which was subsequently used to make model ice cream. The ice cream base containing butterfat, lecithin, xanthan gum, sugar, skimmed milk and double cream was passed over the SDR disc spinning at 2900 rpm, heated at 80 °C and at a flow rate 6 mL s⁻¹. The physical properties of the SDR-processed ice cream base such as particle size and viscosity measurments, and of model ice cream including overrun, meltdown rate and sensory perception were investigated. The SDR-processed ice cream base exhibits narrow particle-size distribution (average particle d ₃₂ = 1.65 μm, d ₄₃ = 2.98 μm) and the viscosity was found to be similar at zero and 18 h ageing, whilst the model ice cream requires zero-hour ageing and has a high overrun value (∼85%) and slow meltdown rate as compared with a commercial sample. The results reveal that the SDR is capable of producing a highly stable ice cream base that requires significantly less ageing than the 18 h typically associated with the traditional process of making ice cream. The SDR process provides intense mixing of ingredients which facilitates the hydration of milk proteins and stabilisers.     

毛细管电泳法直接分离测定果冻中的色素

建立毛细管电泳法直接测定果冻中亮蓝、胭脂红、柠檬黄的方法,研究缓冲溶液种类、浓度、pH值、电压等对分离的影响,并对分离条件进行优化。在波长255nm、分离电压18kV、pH8.5、5mmol/L Na2HPO4-5mmol/L Na2B4O7溶液中,亮蓝、胭脂红、柠檬黄在6min内得到了较好的分离。用于部分市售果冻样品的测定,得到较满意结果,回收率为85%～110%。     

Thermal Degradation of Black Raspberry Anthocyanin Pigments in Model Systems

SUMMARY— The thermal degradation of anthocyanin pigments of black raspberries as influenced by pH, oxygen, sugars and their degradation products were studied. The degradation of the major anthocyanin component (cyanidin-3-digluco-side), the total isolated pigments and the pigment in the natural berry juice was retarded as the pH decreased. Under the same conditions, cyanidin was much more unstable than any of the anthocyanin containing systems. In all cases studied, replacement of the oxygen atmosphere with nitrogen enhanced pigment stability. The rate constants for the thermal degradation of cyanidin-3-diglucoside at various pH levels under oxygen and nitrogen were determined. The sugars studied accelerated pigment destruction to the same extent. Sugar degradation products were more effective than sugars in accelerating anthocyanin breakdown.     

影响高效液相色谱法测定葡萄酒中苋菜红含量的因素分析

运用高效液相色谱（HPLC）法测定葡萄酒样品中着色剂苋菜红的含量,并对测量过程中相关因素引入的测量结果不确定度进行评定,通过对各不确定度分量的分析发现：在测量过程中检验方法、操作人员的熟练程度、仪器设备性能引入的不确定度分量是影响合成不确定度大小的关键因素。     

Ice Recrystallization Inhibition in Ice Cream by Propylene Glycol Monostearate

ABSTRACT: The effectiveness of propylene glycol monostearate (PGMS) to inhibit ice recrystallization was evaluated in ice cream and frozen sucrose solutions. PGMS (0.3%) dramatically reduced ice crystal sizes in ice cream and in sucrose solutions frozen in a scraped‐surface freezer before and after heat shock, but had no effect in quiescently frozen solutions. PGMS showed limited emulsifier properties by promoting smaller fat globule size distributions and enhanced partial coalescence in the mix and ice cream, respectively, but at a much lower level compared to conventional ice cream emulsifier. Low temperature scanning electron microscopy revealed highly irregular crystal morphology in both ice cream and sucrose solutions frozen in a scraped‐surface freezer. There was strong evidence to suggest that PGMS directly interacts with ice crystals and interferes with normal surface propagation. Shear during freezing may be required for its distribution around the ice and sufficient surface coverage.     

Effect of biopolymers on structure and ice recrystallization in dynamically frozen ice cream model systems

Ice crystal growth and microstructure of sugarsolutions prepared with stabilizers (carboxymethyl cellulose [CMC], xanthan gum, locust bean gum [LBG], and gelatin) with or without milk solids-nonfat (MSNF) after freezing in a scraped surface heat exchanger and temperature cycling (5 cycles from -6 degrees C to -20 degrees C) were studied. Ice crystal growth was calculated from brightfield microscopic images acquired from samples before and after cycling. Freeze-substitution and low-temperature embedding (LR-Gold resin) were sample preparation techniques utilized for structure analyses by light microscopy and transmission electron microscopy. Differential staining for carbohydrates and proteins allowed the identification of stabilizer gel-like structures in LBG, gelatin, and gelatin/MSNF solutions. In the absence of milk proteins, xanthan and LBG were the most effective at retarding recrystallization, while in their presence, only xanthan had an effect. Cryo-gelation of the LBG was observed but is not the only mechanism of stabilizer action. Thermodynamic incompatibility between biopolymers was observed to promote localized high concentrations of milk proteins located at the ice crystal interface, probably exerting a water-holding action that significantly enhanced the stabilizer effect. Qualitatively, solution heterogeneity (phase separation) was directly proportional to ice crystal growth inhibition. It is suggested that water-holding by stabilizer and proteins, and in some cases steric hindrance induced by a stabilizer gel-like network, caused a reduction in the kinetics of the ice recrystallization phenomena and promoted mechanisms of melt-regrow instead of melt-diffuse-grow recrystallization, thus resulting in the preservation of the ice crystal size and in a small span of the ice crystal size distribution.     

冰淇淋生产中的凝冻

阐述了冰淇淋凝冻过程及其对制冷的要求,凝冻时间和凝冻机的类型对产品质量的重要性,以及连续式凝冻机和间歇式凝冻机的凝冻过程.凝冻是冰淇淋制作中的一个重要工序,它对冰淇淋的质量、可口性和产率都有较大影响.凝冻过程的作用是冻结冰淇淋混合物中的部分水,并把空气混入混合物,最后指出如何控制冰淇淋的膨胀率.     

Recrystallization in Ice Cream as Affected by Stabilizers

Addition of locust bean gum (LBG) or guar gum to ice cream mixes gave products with smaller ice crystals after heatshock than control samples without either stabilizer. LBG was more effective at inhibiting recrystallization than guar. Increasing stabilizer concentration resulted in greater inhibition. With LBG we found some evidence for an optimum concentration above which no further inhibition occurred. We found no evidence for phase volume effects.