可可脂与代可可脂

本文简述天然可可脂、月桂酸型代可可脂,非月桂酸型代可可脂、类可可脂的结构,特性并介绍各种代可可脂生产工艺特点及其用途。     

可可脂的结晶特性对巧克力质量的影响

<正> 巧克力的物理性质很大程度上取决于制造过程中所用的可可脂质量,特别是可可脂融化、结晶和固化的方法。以下将对可可脂在巧克力制造过程中的物理与化学特性,以及各种可可脂如何充分地改变巧克力的风味、易碎程度及口感进行讨论。 可可脂的结晶性 晶形的形成 由于可可脂具有复杂的结晶性,可通过多种不同的变性而结晶成多晶型脂肪,正是这些     

乳化剂对可可脂结晶行为的影响

从结晶热力学、动力学及形态学3个方面考察了5种乳化剂对可可脂结晶行为的影响。结果表明:单甘脂的添加降低了可可脂在25～30℃温度范围内的固体脂肪含量,不利于巧克力的加工。山梨醇酐单硬脂酸酯(Span60)的添加使可可脂晶体的三维球晶生长方式向二维平面晶体生长方式转变,并显著加快可可脂的结晶速率。Span60和聚乙氧基硬脂酸山梨糖醇(Tween60)缩短了可可脂的半结晶时间,而单甘脂、卵磷脂及聚甘油多聚蓖麻酸酯(PGPR)使可可脂的半结晶时间延长。偏光显微镜结果表明乳化剂的添加使得可可脂球晶的直径增大。     

从硬脂中分提结晶提取代可可脂的研究

由精棉籽油经氢化和利用溶剂分提结晶可获得代可可脂,同时也生成硬脂和软脂,使得代可可脂生成率不高。正是从提高代可可脂的得率这一思想出发,着重阐明了从硬脂中再经溶剂分提结晶提取代可可脂的可行性和方法。     

代可可脂与可可脂相容性及晶体形态研究

利用等温相图和偏光显微镜技术,对可可脂(CB)含量1%～9%的氢化棕榈仁油(HPKO)混合物(HPKO/CB)的相容性及晶体形态进行了研究.结果表明,在0～35 ℃范围内相容性良好,但在15 ℃和20 ℃时HPKO对CB的敏感度高于其他温度.晶体形态分析表明,CB和HPKO晶体形态显著不同,添加少量CB就会出现明显的共晶现象.     

代可可脂、类可可脂、天然可可脂的组成及性质分析

对代可可脂(月桂酸型和非月桂酸型)、类可可脂、天然可可脂的组成及性质进行比较研究,主要包括Sn-2位和总脂肪酸组成分析、熔化特性、产品成分和氧化稳定性分析。结果表明,天然可可脂和类可可脂脂肪酸组成较相似,但与代可可脂则差异较大;天然可可脂、类可可脂和月桂酸型代可可脂的DSC曲线图上出现一个陡峭而又强烈的吸收峰,表明熔化范围较窄,成分单一,而非月桂酸型代可可脂的DSC曲线图上出现两个吸收峰,表明熔化范围较宽,成分复杂;天然可可脂、类可可脂和代可可脂中甘三酯含量均大于94%;利用Rancimat测定的天然可可脂、代可可脂的氧化稳定性相对类可可脂的较好。     

聚甘油脂肪酸酯对可可脂结晶特性的影响

可可脂(CB)是巧克力及巧克力制品的主要成分,其热力学及结晶特性决定了产品的品质、加工特性和货架期。以聚甘油单硬脂酸酯31S、61S和聚甘油蓖麻醇酯(PGPR)为研究对象,利用差示扫描量热(DSC)和X射线衍射技术,研究乳化剂种类、添加量、变温条件对可可脂结晶特性的影响。研究发现:调温温度下,31S和61S具有促进可可脂结晶从Ⅳ型向Ⅴ型转变的效果;而PGPR在添加量大于0.1%的情况下,则表现出对Ⅳ型向Ⅴ型转变的抑制效果;在变温条件下,31S和61S具有促进可可脂热力学亚稳定态晶型的形成和晶型转换的效果,特别是促进了可可脂Ⅱ型晶型的形成,而PGPR无显著影响。     

一种低热代可可脂的相容性研究

采用等温曲线和ΔSFC曲线分析法,研究了自制短长碳链低热代可可脂(LCSL)与市售可可脂(CB)、非月桂酸类代可可脂(CBR)、月桂酸类代可可脂(CBS)、类可可脂(CBE)产品的相容性,结果表明:LCSL与市售产品在低温下的相容性较好,其中与CBS的相容性最好,温度低于20℃时LCSL与CBS可任何比例相容;LCSL适合完全取代CB用于生产糖果或巧克力制品,且在配方中需控制CB含量低于5%。     

可可脂非等温结晶动力学研究

采用DSC 研究可可脂在非等温条件下的结晶行为。结果表明,可可脂随降温速率增加,结晶峰向低温移动,峰强度增加,双峰逐渐变为单峰。用Ozawa 法、Jeziorny 法和莫志深法对结果进行分析并对3 种方法的效果进行对比,结果表明：莫志深法适合作为描述可可脂非等温结晶的数学模型;可可脂结晶度随降温速率提高而增加,其原因是结晶速率的加快。     

可可脂与代可可脂的GC-MS鉴别分析及应用

采用气相色谱-质谱联用法(GC/MS)快速分析可可脂(CB)及代可可脂(CBS)的脂肪酸组成,找出两者组分的显著不同,以此作为鉴别可可脂与代可可脂的依据。结果显示:代可可脂(CBS)中月桂酸占脂肪酸总量的49.083%。可可脂(CB)中主要脂肪酸为硬脂酸,占脂肪酸总量的34.488%;油酸,占31.919%;可可脂中无月桂酸成分。月桂酸的检出与否可作为判断代可可脂(CBS)是否存在的定性依据。     

蔗糖形态对氢化棕榈仁油/可可脂混合体系结晶性质的影响

以氢化棕榈仁油/可可脂(质量比9∶1)混合体系为基料油,采用差示扫描量热仪(DSC)考察不同形态蔗糖(结晶糖、糖粉)和卵磷脂对熔化结晶性质的影响。结果表明:未添加卵磷脂时,蔗糖形态对基料油的熔化结晶性质影响不大;添加卵磷脂后,蔗糖颗粒越细,熔化和结晶温度越高;两种形态的蔗糖体系,添加卵磷脂均使结晶温度显著降低。     

Enzymatically modified tea seed oil as cocoa butter replacer in dark chocolate

Cocoa butter replacer (CBR) was prepared by enzymatic interesterification of hydrogenated and solid fraction (SF) of tea seed oil at weight percent ratio of 30:70, using sn‐1,3 specific lipase from Thermomyces lanuginosus. Dark chocolate samples were then prepared with the prepared CBR as a replacement for 5%, 10%, 15% and 20% of cocoa butter (CB) and the effect of the replacement on hardness (as a key quality factor in chocolate) of the chocolate samples was investigated. Results showed that chocolate samples containing 5% and 10% of interesterified sample (EIS), had the closer texture to that of CB chocolate than other samples. The solid fat content (SFC) profiles also revealed that blending 10% of EIS with CB in chocolate formulation dose not affect the sharp melting point of CB. Based on the results taken from bloom formation, polymorphic structure and sensory evaluation, adding up to 10% of EIS in chocolate formulation reduces the bloom development without adverse affecting the desirable β crystal formation and sensory qualities in the chocolate samples.     

可可脂在非等温条件下结晶及融化特性的研究

采用差式扫描量热仪(DSC)研究了升降温速率和乳化剂对可可脂非等温结晶和融化过程中晶体衍变过程的影响。结果显示:可可脂结晶和融化过程都对温度变化速率(λ)敏感,随λ的提高,放热峰和吸热峰强度均增大,峰值(Tp)则分别降低和升高;单甘酯促进可可脂组分分离,降低结晶温度,改变晶体的融化特性;卵磷脂则提高可可脂结晶温度,对融化特性不产生影响,添加单甘酯和卵磷脂都使可可脂结晶量增加。      

Quality of Malaysian cocoa butter during storage

Malaysian pure prime pressed and deodorised cocoa butters were obtained from local cocoa grinders and analysed for quality deterioration. Approximately 5 kg of each sample was packed in corrugated paper boxes lined with low‐density polyethylene plastic material of thickness 73.2 µm. The water vapour transmission rate and gas transmission rate (for oxygen) of the plastic material were 3.21 g m^?2 day^?1 (37.8 °C, 90 ± 2% RH) and 71.57 cm³ m^?2 day^?1 (23.0 °C, 0% RH) respectively. The butters were stored at 15 ± 4 °C and 70 ± 4% RH for up to 24 months. Samples were taken every 2 months and analysed for free fatty acid content, saponification value, iodine value, refractive index and peroxide value. The findings indicated that the free fatty acid content, iodine value and peroxide value of both types of cocoa butter increased with storage duration. The other parameters showed no significant changes. However, the free fatty acid content and peroxide value after 24 months of storage were still below the limits specified in Malaysia. Therefore we conclude that both types of Malaysian cocoa butter are still in good condition after 24 months of storage, with minimal quality deterioration. Copyright © 2004 Society of Chemical Industry     

Macronutrient profile in milk replacer or a whole milk powder modulates growth performance,feeding behavior,and blood metabolites in ad libitum-fed calves

Milk replacers (MR) for calves usually contain more lactose and less fat than bovine whole milk (WM). There are insufficient data to determine whether these MR formulations are optimal for calves fed at high planes of nutrition. Thus, the effect of 3 MR formulations and a WM powder were evaluated on growth, feeding behavior, and blood metabolites in 96 male Holstein calves fed ad libitum and with 45.5 ± 4.30 kg (mean ± standard deviation) BW at arrival. Calves were blocked based on arrival sequence, and randomly assigned within block to one of the 4 treatments (n = 24 calves/group): a high-fat MR (25.0% fat, dry matter basis; 22.5% protein, 38.6% lactose; 21.3 MJ/kg; HF), a high lactose MR (44.6% lactose, 22.5% protein, 18.0% fat; 19.7 MJ/kg; HL), a high protein MR (26.0% protein, 18.0% fat, 41.5% lactose; 20.0 MJ/kg; HP), and a WM powder (26.0% fat; 24.5% protein, 38.0% lactose; 21.6 MJ/kg; WP). In the first 2 wk after arrival, calves were individually housed and were fed 3.0 L of their respective liquid feed 3 times daily at 135 g/L. They were then moved to group housing and fed ad libitum until d 42 after arrival. Weaning was gradual and took place between d 43 and 70 after arrival; thereafter, calves were fed solids only. Concentrates, chopped straw, and water were available ad libitum throughout the study. Body weight was measured, and blood was collected at arrival and then weekly thereafter from wk 1 to 12. Weight gain and height were greater in HL than WP calves. In the preweaning phase, HL and HP-fed calves consumed more milk than WP, and HL-fed calves consumed more milk than HF calves. In wk 10, starter feed intakes were lower in HF calves than in the other groups. In the preweaning phase, ME intakes were the same for all treatments. This suggests that milk intakes were regulated by the energy density of the milk supplied. The percentage of calves requiring therapeutic interventions related to diarrhea was greater in WP-fed calves (29%) than HF and HL calves (4%), whereas HP (13%) did not differ with other groups. This was coupled with lower blood acid–base, blood gas, and blood sodium in WP than in MR-fed calves. Calves fed HF had greater serum nonesterified fatty acids compared with other groups, and greater serum amyloid A compared with WP and HL calves. Among the serum parameters, insulin-like growth factor-1 and lactate dehydrogenase correlated positively with ME intake and average daily gain. The high lactose and protein intakes in HL and HP calves led to greater insulin-like growth factor-1 concentrations than in WP-fed calves. Although growth differences were limited among MR groups, the metabolic profile largely differed and these differences require further investigation.     

Effect of adding shea butter stearin and emulsifiers on the physical properties of cocoa butter

The aim of this study was to assess the feasibility of shea butter stearin (SBS) as cocoa butter equivalent (CBE). In this work, the optimal ratio of SBS and cocoa butter (CB) was evaluated by the solid fat content and deviation solid fat content. Emulsifiers added to SBS and CB blends were first screened based on β polymorph level, and mixture regression experiment was designed to obtain the optimized compound emulsifiers ratio, finally the characterization of shea butter chocolate was evaluated by sensory evaluation and texture profile analysis (TPA). The best compatibility was obtained when the mixture ratio of SBS and CB was 20:80, where ΔSFC within a range of 1.5 was shown. The appropriate compound emulsifiers were soy lecithin: polyglycerol polyricinoleate: Tween 60 = 1:1:1. Both sensory evaluation and TPA test showed SBS and CB blends could improve the taste and texture of chocolate with proper emulsifiers addition.     

Effect of cocoa butter structure on oil migration

Oil migration from a high oil content filling into adjacent chocolate causes changes in product quality. The objective of this study was to quantify the oil migration from a cream filling system into cocoa butter, which provided a model for the behavior of chocolate-enrobed confectionery products with a soft, creamy center. Magnetic resonance imaging (MRI) was used to monitor spatial and temporal changes of liquid lipid content. A multislice spin echo pulse sequence was used to acquire images with a 7.8 ms echo time and a 200 ms repetition time using a 1.03 T Aspect Imaging MRI spectrometer. Samples were prepared as a 2-layer model system of cocoa butter and model cream filling. Three methods were used to prepare the cocoa butter: static, seeded, and sheared. Samples were stored at 25 °C for a time frame of 56 d. The rate of oil migration was quantified by a kinetic expression based on the linear dependence of oil uptake by cocoa butter and the square root of the time. Samples showed distinctly different rates of oil migration, as evidenced by quantitative differences in the kinetic rate constant. Practical Application: This work will be helpful to elucidate the influence of crystallization process and structural properties such as crystal nanostructure and crystal habit on the migration of oil through a crystalline fat matrix.     

精炼工艺对可可脂品质的影响

为探究精炼工艺对可可脂品质的影响,对可可脂毛油进行脱胶、脱酸和脱色,分析精炼过程中可可脂理化指标、微量成分的变化情况。结果表明:可可脂精炼后,酸价下降,过氧化值升高,色泽变浅、透明度升高,微量成分生育酚(288. 15～155. 75 mg/kg)、植物甾醇(3 621. 82～2 551. 01mg/kg)、总酚(216. 76～106. 41 mg/kg)、可可碱(130. 89～78. 67 mg/kg)和咖啡因(311. 77～202. 31 mg/kg)的含量均显著降低;在15～30℃,精炼油固体脂肪含量(92. 75%～18. 17%)高于毛油(86. 27%～3. 73%),此外,精炼油的熔化焓值(84. 79 J/g)和结晶焓值(64. 18 J/g)均高于毛油的熔化焓值(78. 45 J/g)和结晶焓值(59. 63 J/g),说明可可脂精炼油比毛油具有更高的热稳定性。因此,精炼工艺能够显著影响可可脂的品质,要重视适度加工在今后的应用。