巧克力起霜的研究进展

本文根据当今研究进展,阐述了引起巧克力制品起霜的机理,即相态分离理论和多晶态转化理论,针对各种不同的起霜原由,提出不同的有效万法以延缓起霜现象的发生。     

棕榈糖对油凝胶基巧克力起霜特性的影响

为探究棕榈糖(PS)在生产耐霜巧克力方面的应用潜能,使用PS(0%、25%、50%、100%)部分或全部代替蔗糖制备油凝胶基巧克力(Choc PS0、Choc PS25、Choc PS50、Choc PS100),并通过测定表面白度、表面晶体形态(偏振光显微镜观测)、晶型(X射线衍射法)、热力学性质(差示扫描量热法),以及感官评价监测在温度循环波动环境(20℃下16 h, 32℃下8 h)中储藏60 d的巧克力品质变化。结果表明：温度循环波动储藏60 d, Choc PS25和Choc PS50具有较低的表面白度指数,白色斑点的大小和数量较少,4个样品均呈现出单一的熔化峰,除了Choc PS25和Choc PS50中仍以β_Ⅴ晶型为主外,其他样品总体表现出β_Ⅴ向β_Ⅵ的晶型转变;温度循环波动储藏前后4个样品在回味、香气和甜味方面的得分差异不显著,而硬度和颜色评分降低。综上,当PS添加量为25%～50%时,巧克力表面白度指数较低,晶型为稳定的β_Ⅴ结晶,感官接受度高,产品的抗起霜稳定性较好,具有生产耐霜巧克...     

Biochemical effect of chocolate colouring and flavouring like substances on thyroid function and protein biosynthesis

Synthetic chocolate colourant, flavourant and the mixture of both were administered to healthy adult male albino rats to evaluate their effect on the nucleic acids metabolism, i.e. deoxyribonucleic and ribonucleic acids (DNA and RNA), total serum protein, thyroid hormons (T₄ and T₃) and nuclease enzymes, i.e. cytoplasmic- and mitochondrial deoxyribonuclease and ribonuclease (DNase and RNase) in brain, liver, and kidneys. Also, the activity of the fundamental enzymes of the oxidative pentose phosphate pathway, i.e. cytoplasmic and mitochondrial glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase (G-6-PD and 6-PGD), as well as total lipids and cholesterol contents in the same organs were studied. Ingestion of the studied food additives significantly increased serum protein, RNA and T₄ hormon, while, DNA and T₃ hormon were insignificantly elevated. In connection with this, the hydrolytic enzymes of nucleic acids (DNase and RNase activities) were stimulated by all studied food additives and in all mentioned organs. The activity of G-6-PD and 6-PGD in both cytoplasmic and mitochondrial fractions of all studied organs were increased. The highest increase was noticed in rats fed on diets supplemented with the mixture of both colourant and flavourant followed by colourant then flavourant, respectively.     

Biochemical effect of chocolate colouring and flavouring like substances on thyroid function and protein biosynthesis.

Synthetic chocolate colourant, flavourant and the mixture of both were administered to healthy adult male albino rats to evaluate their effect on the nucleic acids metabolism, i.e. deoxyribonucleic and ribonucleic acids (DNA and RNA), total serum protein, thyroid hormones (T4 and T3) and nuclease enzymes, i.e. cytoplasmic- and mitochondrial deoxyribonuclease and ribonuclease (DNase and RNase) in brain, liver, and kidneys. Also, the activity of the fundamental enzymes of the oxidative pentose phosphate pathway, i.e. cytoplasmic and mitochondrial glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase (G-6-PD and 6-PGD), as well as total lipids and cholesterol contents in the same organs were studied. Ingestion of the studied food additives significantly increased serum protein, RNA and T4 hormone, while, DNA and T3 hormone were insignificantly elevated. In connection with this, the hydrolytic enzymes of nucleic acids (DNase and RNase activities) were stimulated by all studied food additives and in all mentioned organs. The activity of G-6-PD and 6-PGD in both cytoplasmic and mitochondrial fractions of all studied organs were increased. The highest increase was noticed in rats fed on diets supplemented with the mixture of both colourant and flavourant followed by colourant then flavourant, respectively.     

The effect of high-pressure jet processing on cocoa stability in chocolate milk

Fat-free chocolate milk formulations containing skim milk, cocoa powder, and sugar were thermally treated and then processed using high-pressure jet (HPJ) technology from 125 to 500 MPa. The rheological properties and stability of HPJ-treated chocolate milks were compared with controls (no HPJ processing) prepared both with and without added κ-carrageenan. As expected, carrageenan-free chocolate milk exhibited immediate phase separation of the cocoa powder, whereas formulations containing κ-carrageenan were stable for 14 d. An increased stability was observed with increasing HPJ processing pressure, with a maximum observed when chocolate milk was processed at 500 MPa. The apparent viscosity at 50 s⁻¹ of HPJ-processed samples increased from ~3 mPa·s to ~9 mPa·s with increasing pressure, and shear-thinning behavior (n < 0.9) was observed for samples processed at HPJ pressures ≥250 MPa. We suggest that HPJ-induced structural changes in casein micelles and new casein-cocoa interactions increased cocoa stability in the chocolate milk. Because casein seemed to be the major component enhancing cocoa stability in HPJ-treated samples, a second study was conducted to determine the effect of additional micellar casein (1, 2, or 4%) and HPJ processing (0–500 MPa) on the stability of fat-free chocolate milk. Formulations with 4% micellar casein processed at 375 and 500 MPa showed no phase separation over a 14-d storage period at 4°C. The addition of micellar casein together with HPJ processing at 500 MPa resulted in a higher apparent viscosity (~17 mPa·s at 50s⁻¹) and more pronounced shear-thinning behavior (n ≤ 0.81) compared with that without added micellar casein. The use of HPJ technology to improve the dispersion stability of cocoa provides the industry with a processing alternative to produce clean-label, yet stable, chocolate milk.     

大豆异黄酮巧克力的制备及其对更年期综合症的影响

将大豆异黄酮(大豆染料木素与染料木苷占40%)添加到巧克力配料中,通过单因素实验及正交实验,优化大豆异黄酮巧克力制备工艺。确定更年期女性每人摄入大豆染料木素与染料木苷总量30 mg/d,为具有类雌激素效应的有效摄入量。通过优化,得到最佳工艺为:精磨温度为45℃、精磨时间8 h、精炼温度80℃、精炼时间72 h、调温时间30 min,大豆异黄酮添加量为1.25%、可可液块添加量为9%、可可脂添加量为18%、蔗糖添加量为35%、奶粉添加量为8%、食用植物油添加量为28%、卵磷脂添加量为0.5%、香料添加量为0.25%。最佳工艺条件下制备的大豆异黄酮巧克力对更年期综合症具有一定改善功效。     

螺旋藻巧克力的研制

研究在巧克力液块中添加螺旋藻干粉等物质制成营养更加均衡的螺旋藻巧克力,确定最佳配方为螺旋藻干粉5%、砂糖30%、卵磷脂0.3%和单硬脂酸甘油酯0.4%,并对螺旋藻巧克力的营养成分及理化、微生物指标进行测定分析。     

Volatile fatty acid production in cacao fermentation and the effect on chocolate flavour

The production of the C₃ to C₅ volatile fatty acids during the processing of raw cacao has been studied by means of gas chromatography. These fatty acids are produced towards the end of fermentation and also during the drying phase, if conditions are conducive to this. The time of their appearance is related to the degree of aeration of the fermenting mass. In low concentrations, they may be regarded as contributing to normal chocolate flavour, but higher concentrations, such as are associated with poor conditions of processing, cause “dull”, “insipid” off-flavours. Suggestions are made about the mechanism of their production and the microorganisms that may be involved.     

The functionality of milk powder and its relationship to chocolate mass processing, in particular the effect of milk powder manufacturing and composition on the physical properties of chocolate masses

Summary The functionality of twelve different milk powders that are used for chocolate mass processing was investigated. In two types of spray‐dried and one type of roller‐dried powder, the milk fat and milk fat fractions were integrated. Depending on the production process, the amount of free fat available in the milk powders varied greatly. A good correlation was found between the free fat content of the milk powder and the viscosity of the chocolate mass when comparable particle sizes were used. This study reports on the development of spray‐dried milk powders, which when used in chocolate processing produced low viscosities, comparable with those obtained by using roller‐dried milk powder. Calorimetric analysis showed that the shape of the milk powder particles has no influence on the calorimetric qualities of chocolate masses. Only when milk fat was added in a free form, was a higher ‘mixing effect’ in the crystallization peak of cocoa butter and milk fat observed.     

The effect of viscous substances on the transit time of barley digesta in rats

The influence of a number of hydrocolloids on the transit time of digesta, stool weight and colour of stools was investigated in rats. All hydrocolloids tested gave the stools a lighter colour and increased their size and water content. The hydrocolloids could be divided into two groups according to their action on digesta passage: pectin, gum arabic, oxidised starch and barley β-glucan retarded it, while guar gum, carrageenan, tragacanth gum, carob bean gum, sodium alginate and sodium carboxymethyl cellulose accelerated it. After feeding carrageenan for 1 week it took several weeks before water content and transit time returned to normal. Gum arabic was found to cause caecal distension.     

Structural characteristics of cocoa particles and their effect on the viscosity of reduced fat chocolate

Aimed at the manufacture of reduced fat chocolates, a novel method of trapped fat reduction was assessed: Manipulation of the cocoa ingredient. Cocoa mass was replaced with cocoa powder (11 g/100 g or <1 g/100 g fat) and added ‘free’ cocoa butter. A cocoa solids approach to design reduced fat chocolates with satisfactory flow properties is attractive to industry since it circumvents introduction of ingredients not commonly used in chocolate manufacture. Results showed that the cocoa mass chocolate had a higher viscosity than cocoa powder chocolates of the same total fat content due to the presence of trapped fat globules as identified by confocal laser scanning microscopy. The chocolate prepared with standard defatted cocoa powder containing 11 g/100 g fat had a lower viscosity than the chocolate containing highly defatted cocoa powder (<1 g/100 g) due to particle shape and fat diffusion into the particles as revealed by microscopy analyses. Based on the evidence presented, it can be concluded that standard defatted cocoa powder, as widely used by the industry, is indeed the best compromise in terms of free fat, particle size and morphology attempting to formulate fat reduced chocolate of acceptable molten state viscosity.     

绿色木霉抑菌物质的抗菌效果测定

绿色木霉菌是一种非常具有生防潜力的拮抗菌,其拈抗机制多种多样,包括产生抗生素、重寄生作用、溶菌作用、竞争作用等。本研究对绿色木霉的抑菌物质的抑菌效果进行了测定。研究结果发现绿色木霉发酵代谢物对镰刀菌的抑制率从第4天开始明显增大,第5天的时候达到最大,然后缓慢下降,抑菌率可达到80％;绿色木霉胞内物质的抑菌效果不如发酵代谢物,抑菌率也是先缓慢增大,在第5天的时候抑菌率高达56．9％,然后缓慢下降。研究表明绿色木霉的发酵代谢物和胞内物质对镰刀菌都具有较好的抑菌效果,并且具有防效长久的作用,在生物防治方面有很大的应用前景。     

油炸对黑虎虾关键性风味物质的影响

采用溶剂辅助风味蒸发法-气相色谱质谱联用仪(SAFE-GC-MS),通过双柱定性分别对鲜黑虎虾和炸黑虎虾的挥发性成分进行分析,从鲜虾中共检出81种化合物,炸虾中共检出93种化合物。通过气相色谱-嗅闻-质谱联用(GC-O-MS)和气味活性值(OAV)两种方法分别确定油炸前后黑虎虾的关键性风味成分,结果显示:鲜虾的关键性风味物质为:N,N-二甲基甲酰胺、2-糠酸甲酯、3-羟基-2丁酮、癸醛和庚醛。炸黑虎虾关键性风味物质为:2,3,5-三甲基吡嗪、2,3-二甲基-5-乙基吡嗪、2,5-二甲基-4-羟基-3(2H)-呋喃酮、2,5-二甲基吡嗪、2,5-二甲基-3-乙基吡嗪、2-乙酰基吡咯、吡嗪、5-甲基-2-乙基吡嗪、苯乙醛和反,反-2,4-癸二烯醛。经过油炸,构成黑虎虾的关键性风味物质发生了明显变化,其中,吡嗪类物质的含量显著增加。     

巧克力风味牛奶的研制与开发

近年来市场上出现的巧克力牛奶一般都是用巧克力加牛奶直接配制而成的,由于巧克力热量高,易导致肥胖、高血脂等疾病,因此在市场上的销售受到了一定的限制。本课题通过选用巧克力香精替代巧克力,以鲜牛奶为主要原料,选用L9(33)正交表,通过正交实验筛选最佳配方。试验结果表明鲜牛奶85.0%,复合稳定剂0.16%,巧克力香精0.07%,食用色素0.106%,AK糖0.02%,可可粉0.4%,白砂糖2.0%。产品经分析检测符合国家质量卫生标准,口感细腻,巧克力风味浓郁,奶香突出,色泽诱人,是一种非常有发展前途的新型风味牛奶。     

The effects of the organic acids in cocoa on the flavour of chocolate

Samples (54) of dried fermented cocoa beans from different world regions were analysed for levels of organic acids, pH and titratable acidity. The effects of the organic acids on the flavour characteristics of cocoa were examined by sensory evaluation of chocolate made from samples of cocoa beans. Concentrations (g kg^?1) of acids ranged from 1.3 to 11.8 for acetic, 1-6 to 9-9 for citric, 0.6 to 11.1 for lactic and 2.1 to 6.5 for oxalic. pH values ranged from 4.6 to 5.8, while titratable acidity ranged from 0.08 to 0.31 equivalents of sodium hydroxide per kg sample. Cocoas from South East Asia and the South Pacific tended to be more acidic than West African beans in terms of both chemical and sensory characteristics. Lactic and acetic acids were found to be in greater concentrations in cocoas from the former regions and were considered to be largely responsible for higher acid flavour scores. In contrast, citric and oxalic acids were generally lower in these beans. Flavour assessments of cocoas with and without added organic acids indicated that oxalic acid played an important role in chocolate flavour. These results suggest that a reduction in the levels of acetic and lactic acids only, may not be sufficient to produce a desirable flavour balance.     

麦香巧克力脆粒的研制

将挤压膨化技术与麦香巧克力涂层技术相结合,对麦香巧克力脆粒的工艺流程、技术操作要点及生产中质量控制方法进行研究,成功制作麦香巧克力脆粒,可广泛应用于杯装、棒支、蛋筒类等冰淇淋产品中,提高了冷饮卖点,具有广阔的应用前景.     

不同预处理方法对提取萝卜籽油品质的影响

研究了整粒浸泡酶解、种子粉碎酶解、种子粉碎3种预处理方法对提取的萝卜籽油中多种指标的影响。结果表明,整粒浸泡酶解预处理方法提取的油脂中异硫氰酸酯、莱菔素含量高,总抗氧化能力、清除DPPH·能力强,种子粉碎酶解法次之,种子粉碎法最差;种子粉碎预处理法的油脂中酸价和过氧化值含量最高,种子粉碎酶解法次之,整粒浸泡酶解法最低;3种预处理方法对油脂脂肪酸组成变化不显著。整粒浸泡酶解法提取油脂的条件为:整粒种子25℃浸泡1 h,破碎后25℃酶解50 min,酶解p H5.0,液料比20 m L/g,提取时间5 min;萝卜籽油的提取率为34.51%,提取效率为95.03%。