This research endorses the essential role of quality control for the manufacturing of yoghurt in Lebanon. Related Articles:. Perspective in the History of Science and Technology. Date: September 23, Date: September 30, Globalization of Science and Technology through Research and Development. Date: April 2, Date: October 24, However, it may well have been evident even at an early stage that the souring of milk was by no means a uniform process. Thus, the fermentation brought about by non-lactic acid bacteria gives rise to a product that is insipid and stale and, furthermore, the coagulum is irregular, filled with gas holes and shows extreme whey syneresis.
Lactic acid bacteria, however, act on milk to produce a fermented product that is pleasant to eat or drink; this latter product was usually referred to as sour milk. The animals that are raised by the nomadic peoples of the Middle East are cows, goats, sheep and camels, and gradually the tribes evolved a fermentation process which brought under control the souring of these various milks.
In particular, the process might have included:. Although the evolution of the process was strictly intuitive, the production of sour milk soon became the established pattern of preservation and, since the early s, defined microorganisms have been used to prepare these products on a large scale in factories.
Selection of yoghurt and yoghurt-like products that have been identified in the Middle East and elsewhere. After: Tamime and Deeth , Accolas et al. Around generic names are applied to the traditional and industrialised fermented milk products manufactured throughout the world Kurmann et al. Although these products may have different names, they are practically the same, and a more accurate list might include only a few varieties.
Taking into account the type of milk used, the microbial species that dominate s the flora and their principal metabolic products, Robinson et al. These products have been extensively reviewed by Tamime and Marshall and Tamime et al. Adapted from Robinson and Tamime Although yoghurt has many desirable properties, it is still prone to deterioration, especially at ambient temperature, within a matter of days, and one discernible trend in the Middle East has been the search for simple techniques to extend the keeping quality.
The first step in this process turned out to be relatively simple because the containers traditionally used by the nomads for the production of yoghurt were made from animal skins. In normal use the yoghurt would have been consumed fairly rapidly but, if left hanging in the skin for any length of time, the nature of the product altered dramatically. Thus, as the whey seeped through the skin and evaporated, the total solids content of the yoghurt rose and with it the acidity.
To the nomadic people, whose main sources of wealth and nourishment are the animals that can be raised and the milk that they produce, the relative resistance of the condensed yoghurt to spoilage must have appeared attractive. Evidence of this trend can be found in Armenia where the mazun Armenian yoghurt is usually pressed to yield a product called tan or than. Similarly, surplus milk production in remote villages in Turkey is turned into concentrated yoghurt by the daily addition of milk to yoghurt hanging in goat or sheep skins.
Another method of concentration of yoghurt is where the product is placed in an earthenware vessel; the Egyptians call this product leben zeer. Nevertheless, even condensed yoghurt becomes unpalatable within a week or two, and it was for this reason that salted yoghurt rapidly became popular. Salting is an age-old method used by humans to preserve food, but the incorporation of salt into concentrated yoghurt also acts as a neutralising agent to reduce the acid taste of the product; different types of concentrated yoghurt are made in Turkey by the addition of various quantities of salt.
Afterwards the yoghurt balls which are partially dried are placed in either glazed earthenware pots or glass jars and covered with olive oil. An alternative preservation process involves heating yoghurt for a few hours over low fires of a special type of wood; the end product is referred to as smoked yoghurt.
This type of yoghurt is also preserved over the winter months by placing it in jars and covering it with either olive oil or tallow.
Manufacture of Yoghurt and Other Fermented Milks | SpringerLink
In some countries Turkey, Lebanon, Syria, Iraq and Iran the concentrated yoghurt is processed even further to produce a totally different product of almost indefinite keeping quality. This is a dried form of yoghurt; milk is processed into yoghurt in the traditional manner and wheat flour, semolina or parboiled wheat, known locally as burghol, is rubbed into it. This product is called kishk and it is sold either as nuggets for flavouring local dishes or in a ground-up form as flour see Chapter 5.
Kishk as a dish is prepared by reconstituting the yoghurt—wheat mixture with water and then simmering the mix gently over a fire. The consistency of this product, which is normally consumed with bread, is similar to porridge. The concentrated yoghurt can be also processed into a different product called shankleesh Toufeili et al. Here again the product is partially dried, but is then mixed with spices and herbs presumably to assist in preservation.
The mixture is then formed into balls, placed into glass jars and finally covered with olive oil. It is evident that many different products can be manufactured from yoghurt, and Fig. As refrigeration became widespread, so interest in these traditional products declined, except among certain communities in the Middle East. Initially, production was confined to natural yoghurt and the market was limited, in large measure, to those who believed that yoghurt was beneficial to health.
Gradually, however, attitudes towards yoghurt changed, and the advent of fruit yoghurts during the s gave the product an entirely fresh image. Instead of being a speciality item for the healthfood market, it became a popular and inexpensive snack food or dessert. Production figures reflect the expanding market. However, in Lebanon in , the economic value of Ayran i. Per capita annual consumption kg head—1 of fermented milks in some selected countries. Per capita annual consumption kg head—1 of milk drinks and fermented products including yoghurt in some selected countries.
Table 1. It is evident from Tables 1. However, the consumption of buttermilk is not properly classified in most countries because: a traditional or natural buttermilk is the by-product of butter making from ripened or cultured cream, b cultured buttermilk is produced by the fermentation of skimmed milk with the addition of butter flakes, and c there is sweet buttermilk which is not fermented; the data for buttermilk shown in Table 1. Nevertheless, fermented milk products made with mesophilic lactic acid bacteria see Fig. The methods of production of yoghurt have, in essence, changed little over the years.
Although there have been some refinements, especially in relation to lactic acid bacteria that bring about fermentation, the essential steps in the process are still the same:. At present there are many different types of yoghurt produced worldwide, and Tamime and Deeth have proposed a scheme of classification that separates all types of yoghurt into four categories based on the physical characteristic of the product.
This approach is illustrated in Table 1. However, these products and in particular yoghurt are subdivided into different groupings based on the following aspects:. Figure 1. The inclusion of these varieties under the banner of yoghurt offends some people, because yoghurt per se must, by virtue of the process, contain an abundance of viable bacteria originating from the starter culture. However, popular usage appears to have determined that, as long as a carton is clearly labelled with information about the nature of the finishing process, for example, pasteurised yoghurt, then the consumer should understand that the integrity of the basic product has been compromised.go
Tamime and Robinson's Yoghurt
Thus, the chill cabinets of many supermakets in Europe, North America and Australasia have shelf-space allocated to yoghurt-like products fermented with probiotic bacteria, i. In countries such as France, companies, e. In the USA, probiotic products can be labelled as yoghurt so long as nominal counts of S. Gelled or semi-solid, milk-based foods in which the basic structure has been derived by a fermentation stage involving a range of specific organisms of starter origin.
In effect, this definition accepts the current commercial reality in the United Kingdom for, while the counts proposed in the Codex Standard appear helpful, in practice it would be impossible to produce a yoghurt of acceptable quality with a total count of starter organisms below 1. Variations in milk composition, irregular behaviour of the starter organisms, faulty regulation of the incubation temperature, along with a number of other process variables, can all give rise to an end product that is deficient in respect of overall quality, and only a thorough understanding of the fermentation can provide an operative with the foresight to reduce the risk of product failure.
It is with this background in mind that the relevant issues have been isolated for discussion, for although the different steps in production are interrelated, it is convenient to discuss them within the confines of an individual compartment. The following chapters are a reflection of this view. International Journal of Food Microbiology.
In: Short Life Dairy Products. Paris: Centre de Receherche Daniel Carasso; Danone Vitapole. Journal of the Society of Dairy Technology. Campbell-Platt C. Fermented Foods of the World.
El-Gendy SM. Council Regulation EC No. Official Journal of the European Commission. In: Smith BL, ed. Codex Alimentarius — Abridged Version. Hickey M. In: Oxford: Blackwell Publishing; — Tamime AY, ed.
Probiotic Dairy Products. In: Brussels: International Dairy Federation; —4. In: Doc.
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