巧克力之生产、方法及精制效果

脂肪(吸墨纸);由此产生的质量将更紧密，具有泥浆的稠度，因此它可以更容易地转移上输送带输送至精炼作业。精炼机的特点是5个滚筒几乎垂直安装在另一个上面，并通过冷水循环，就像预精炼机一样。精确调整滚筒之间的距离(间隙)，以获得最高的精炼细度。用于调整“间隙”的系统可以是:机械的或气动的，也可以是上一代精炼机——电子的。从第一个辊到最后一个辊，转速逐步提高，在从慢辊向快辊移动(从下到上流动)的同时，产品也被压碎和拉伸。转速约为。第一辊0.75米/秒，第二辊1.25米/秒，第三辊1.80米/秒，第四辊2.45米/秒，第五辊3.70米/秒。与预精炼机的滚筒不同，精炼机的滚筒必须是凸形的，以补偿因努力而引起的滚筒弯曲，以及因摩擦产生的热量而产生的先天延伸，从而保证均匀精炼。合适的刀片，与滚筒的整个长度相切，将从表面分离巧克力薄膜。在最初的精炼机中，通常有3个滚筒，必须将质量进行2到3次处理，以获得所需的粒度。 On the new 5 roller refiners, a fineness up to 18-20 micron can be achieved in a single process. In some cases, the particle size even reached smaller values, but there is no evidence that “the game is worth the candle”, because palate sensitivity does not allow the identification and distinction of this kind of fineness. It is a fact that human lingual papillae allow to detect particles measuring not less than 25 micron, which means that larger particles can be perceived as “grains” or “sand”. Apparently, hence, from a merely technological point of view, it should be guaranteed that chocolate particles have a maximum size of less than 25 micron.

电子控制辊压
然而，味觉的感觉不仅取决于颗粒的大小，还取决于不同颗粒中存在的数量。这意味着在存在大量大于指定阈值的颗粒时，可以感觉到粗糙。还应提醒的是，高级研磨会产生“贪吃脂肪”(吸纸效应)的产品，通常具有降低的流变特性。机器的能力取决于轧辊的长度(目前的精炼机可以配备1300到2500毫米长的轧辊)和产品的类型。通常生产能力在500公斤/小时到1000公斤/小时或更多。由于乳糖的存在，牛奶巧克力和含有牛奶的类似产品更难提炼。使用精炼机总是需要相当的经验和细心;事实上，应该提醒的是，这是一个单一的段落，这允许很小的误差。最近引入电子控制辊压，导致重新考虑与熟练操作人员工作的需要;但是，不应遵守几个基本参数忽略:流经辊筒的冷却水温度不得超过30℃;机器不允许空转。如果巧克力块堆积在辊筒的一侧，则必须调整相关辊筒之间的“间隙”;而当部分区域没有被巧克力覆盖时，则需要减慢冷却水的流动速度，因为这个问题是由于冷却过度造成的。刮刀应始终非常锋利，以保证能从滚轮表面去除大块。在精炼过程中，产品的物理性质和流动性质发生了很大的变化;事实上，在生产过程的出口，所获得的质量主要是由难以察觉的粉末组成的，这些粉末将被转移到下一个操作中——通常是通过传送带的方式:conching。正如前面所描述的，有几种不同的细化方法，尽管最流行的是上面描述的那种。然而，这种滚筒精炼系统也有变化;事实上，有时用糖粉代替冰糖。 This change, although apparently of little importance, becomes relevant if one takes into account that the pre-refining operation can be avoided. Years ago this processing technology was widely used, but for two reasons it has been partly abandoned: 1) Crystal sugar had to be ground on site, because the one available on the market, for its preservation, contains 4-5% of starch that may negatively affect the final product structure; 2) A higher need of fat (cocoa butter) 27-29% due to the high adsorption power of powdered sugar compared to crystal sugar. The most popular alternative to roll refining is represented by the use of Ball Mills. This processing method practically replaces the whole line described above; it is widely used for the production of anhydrous creams and surrogates, as well as – in many countries – for the production of chocolate and dried fruit, as well as for semi-finished products as nougat paste, etc. The ball mixers technology comes from the world of paints and inks, and was already in use in the 1920. In the ‘50s it was used with excellent results in the confectionery sector by the Dutch company Wiener for grinding roasted cocoa. The ball mill mainly consists of a double chamber roller used both for heating and cooling, inside which a considerable amount of steel balls are moved by a central shaft equipped with special arms or disks. A ball mill refining system practically replaces a conventional processing plant integrating mixing, pre-refining, roller refining and conching, although with capacities. The ingredients are mixed in a vertical or horizontal tank, and the highly liquid mass resulting from this process is then pumped into the ball mill. In order to obtain a fineness very similar to that obtained with roller refining, normally this process has to be repeated several times; not always with positive effects. In fact, some parameters, especially viscosity, flowability and formation of sub-fine particles, that notably affect the mass plasticity, can undergo to considerable changes. As already said, the ball mill refining system replaces the conching phase. Synthetically said, ball mill refining is an excellent alternative to roller refining technology, especially as far as the costs of the system and its management are concerned; albeit end results are not always compatible. For instance, if all goes well, the grain size reaches 22-25 micron; the temperature cannot always be effectively controlled; finished products often have a metal taste; products containing milk tend to over-heat, causing a degeneration of proteins and a modification of the structure; finally, for a good processability, the fat content should be of at least 30%.

由天奴Carrega