Vinegar, production

Various species and many strains oiyAcetobacter are used in vinegar production (48,49). Aeration rates, optimum temperatures and nutrient requirements vary with individual strains. In general, fermentation alcohol substrates require minimal nutrient supplementation whde their addition is necessary for distilled alcohol substrates. 

The most widely used submerged-culture oxidizer is the Brings acetator (50). It uses a bottom-driven hoUow rotor turning in a field of stationary vanes arranged in such a way that the air which is drawn in is intimately mixed with the Hquid throughout the whole bottom area of the tank (51,52). In the United States, continuous cavitator units are used widely for cider-vinegar production. 

In fermentation for the production of acetic acid, ethyl alcohol is used in an aerobic process. In an ethanol oxidation process, the biocatalyst Acetobacter aceti was used to convert ethanol to acetic acid under aerobic conditions. A continuous fermentation for vinegar production was proposed for utilisation of non-viable A. aceti immobilised on the surface of alginate beads. 

Immobilization is the technique of choice in many food industry processes and especially in beverage production. Many immobilization technologies have already been tested and some are applied in the production of beer, wine, vinegar, and other food products using a traditional approach with cultme adhesion (i.e., Acetobacter in vinegar production) or more modem approaches with entrapment of yeast biomass (i.e., sparkling wines, cheeses, and yogurts). 

Some raw materials used for vinegar production are listed in Table 1. 

Acetic acid (CH3COOH) is a bulk commodity chemical with a world production of about 3.1 x 106 Mg/year, a demand increasing at a rate of +2.6% per year and a market price of US 0.44-0.47 per kg (Anon., 2001a). It is obtained primarily by the Monsanto or methanol carbonylation process, in which carbon monoxide reacts with methanol under the influence of a rhodium complex catalyst at 180°C and pressures of 30-40 bar, and secondarily by the oxidation of ethanol (Backus et al., 2003). The acetic fermentation route is limited to the food market and leads to vinegar production from several raw materials (e.g., apples, malt, grapes, grain, wines, and so on). 

Recombinant strains of Acetobacter aceti, cloned with either alcohol dehydrogenase or aldehyde dehydrogenase, have been tested for vinegar production. The bacteria with the aldehyde dehydrogenase gene produced acetic acid more rapidly than those with the alcohol dehydrogenase, and were more resistant to high concentrations of acetic acid. 

Hanseniaspora uvarum (anamorph Kloeckera apiculata) is commonly the major yeast present on the grape berry and in musts and juices, but due to low tolerance to ethanol, populations decline quickly in the presence of Saccharomyces cerevisiae. Strains are typically characterised by low fermentative ability and high production of acetic acid, ethyl acetate and acetaldehyde, which render such strains more suitable to vinegar production. Nevertheless, Ciani and Maccarelli (1998) surveyed 37 isolates and found considerable variability, with some strains producing concentrations of these compounds approaching concentrations present in wines made with Saccharomyces cerevisiae (Table 8D.6). Cofermentation fermentation with Saccharomyces cerevisiae can produce wines with an acceptable balance of volatile and non-volatile compounds and sensory scores (Ciani et al. 2006 Jemec and Raspor 2005 Jolly et al. 2003b Zohre and Erten 2002). 

The second possibility is to use a liquid culture. In this case it is possible to use already fermenting vinegar or a special liquid culture. Dried formulations such as fermenting yeasts are unfortunately not yet available for vinegar production. 

Temperature is an important factor in vinegar production. Like all bacteria, vinegar bacteria prefer warm conditions. Temperatures around 25°C are essential for rapid and effective fermentation. If the temperature of the vinegar falls markedly during fermentation, the fermentation process is interrupted and may start again later. The temperature in the vinegar vat should therefore never drop below 25°C. 

Containers which have been used for vinegar production are no longer suitable for the production or storage of other products. They are usually so heavily contaminated with vinegar bacteria that other products stored in the container would inevitably acquire a vinegary flavour. The exception is stainless-steel containers, which can be disinfected with suitable cleaning products. 

Submerged fermentation processes are currently considered to be the best methods of vinegar production. The bacteria are active in the liquid, no mother of vinegar is produced, and continuously controlled aeration is guaranteed. This means that temperature control and thus carefully... 

Joint use of IRs (D/H the isotopic ratio 813C%o = 1000 x (R sample Rreference)/Rreference> calculated on the reference international standard), some elements (Na, Sr, V, Rb) and anions (nitrate, chloride) gave positive results also for distinguishing mute and concentrated musts used for balsamic vinegar production from three Italian regions. Canonic... 

Figure 8.9 Plot of the canonic discriminant analysis carried out for mute and concentrated musts used for balsamic vinegar production from three Italian regions...

Ciani, M. (1998). Wine vinegar production using base wines made with different yeast species. J. Sci. Food Agric. 78, 290-294. 

Sievers, M. and Teuber, M. 1995. The microbiology and taxonomy of Acetobacter europaeus in commercial vinegar production. Journal of Applied Bacteriology 79 84-95. 

Trcek, J., Raspor, P., Teuber, M. 2000. Molecular identification of Acetobacter isolates from submerged vinegar production, sequence analysis of plasmid pJK2-l and application in the development of a cloning vector. Applied Microbiology and Biotechnology 53 289-295. 

Shahidi et al. (1999) reported that production of dietary cookies, potato chips, and noodles enriched with chitosan is commonplace in certain countries. The products enriched with chitosan have high hypocholesterolemic effects. In addition, vinegar products containing chitosan are produced and sold in Japan because of their cholesterol-lowering ability (Shahidi et al., 1999). 

In Japan, continuous production processes using immobilized living cells are currently introduced in such classical areas as beer (Kirin Brewery Co.) and sake brewing (Ohzeki, Co. Ltd), vinegar production (Kewpie Jyozo, Co. Ltd), and in the production of soy sauce (Kik-koman Co.). 

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