Title of Invention

AN IMPROVED PROCESS FOR THE PREPARATION OF BREWED VINEGAR FROM ONION

Abstract

Accordingly, the present invention provides an improved process for the preparation of brewed vinegar from onion, which comprises, (i) descaling manually or mechanically the outer dried scales of the bulbs, (ii) cleaning of desacaled bulbs using potable quality water for the removal of cross-contaminants and other extraneous matter, (iii) slicing of descaled and cleaned onion bulbs so as to facilitate pulping (iv) pulping of the onion slices by using a mechanical device, (v) extracting the juice enzymatically from the pulp and inactivating the enzyme by heat treatment for a period of 20-40 minutes, (iv) preparing an alcoholic fermentation of extracted onion juice by using a facultative microorganism for 5-6 days by incubation at 28-34°C and converting the alcohol to acetic acid by a strict aerobic microorganism at 28-35°C for 4 - 5 weeks to obtain the desired brewed vinegar of 4-5% acetic acid and the characteristic

Full Text

The present invention relates to an improved process for the preparation of brewed vinegar from onion. The process relating to the preparation of brewed vinegar from onion bulbs which has the original seasoning and condiment effect of a traditional vinegar is disclosed. More specifically, the steps of descaling, cleaning, slicing, pulping and enzyme treatment of onion bulbs are performed to obtain a clear juice which is converted to an alcoholic ferment using optimal cell density of the yeast culture, Saccharomyces cerevisiae. The alcoholic ferment is made free from the yeast cells and the clear ferment is mixed with requisite quantities of mother vinegar from a previous batch resulting in 1.0-1.5% acetic acid. Fermentation of the mixture is carried out under static and accelerated conditions to achieve a vinegar product from onion bulbs with 4-5% acetic acid content. Brewed vinegar is a solution of acetic acid produced by a two-stage fermentation process. In the first stage, fermentable sugars are converted into ethanol by the action of yeasts (normally strains of Saccharomyces cerevisiae), while in the second stage, bacteria of the genus Acetobacter oxidize the ethanol to acetic acid. The brewed vinegar is prepared from a variety of natural substrates which contain fermentable sugars. Commercially, the vinegars available in market are genuine brewed vinegar, synthetic vinegar and partially adulterated brewed vinegar. Vinegar is used both, at house-hold and industrial levels. Reference may be made to the document on the vinegar in the Wealth of India (1976), it has been stated that the microbiological nature of vinegar fermentation was known hardly around 1850. Different types of generators were designed for the production of vinegar rapidly and efficiently (Nathaniel 1952). Acetic acid is the chief constituent in the vinegar. Minor constituents include varying amounts of non-volatile organic acids, glycerol, sugars, alcohol, aldehyde, acetyl methyl carbinol, phosphates, chlorites and sulphites of calcium, potassium and other cations. The minor constituents are responsible for characteristic taste and aroma and determine the quality of the product. This explains the higher cost and demand of the brewed vinegar over the synthetic one. The later is inferior in taste and aroma, which is described as 'harsh'. Brewed vinegar is a highly priced culinary item of traditional food products such as vinegar spice extracts, meat gravis, fish curries, chutneys, sauces, pickles and other related items. Considerable amounts of brewed vinegar enters international trade due to its demand for preservation of brined vegetables. Brewed vinegar is also in great demand for its characteristic flavour by consumers of pickled vegetables like olive, gerkins, cucumbers, etc. It is also claimed, that vinegar helps to improve the quality of cooked meat and fish leading to enhanced digestibility. Besides, the preservative action of vinegar is due to its acetic acid content. As little as 0.1% of the undissociated acid will inhibit the growth of most food poisoning and spore-forming bacteria and at 0.3% concentration will prevent the growth of mycotoxigenic molds. Reference may also be made to various raw materials used for making brewed vinegar. Juices of fruits such as grape, apple, sweet orange, phalsa, jamon, pear, loquot, peach, plum and apricot; gur (jaggery), molasses, sugarcane juice, starches, acid and enzymic hydrolysates of starches, polysaccharides and fruit waste such as pineapple waste (Wealth of India 1976). Vinegar is also made from honey (Fabian 1926). Reference may further be made to quality parameters of brewed vinegar. Brewed vinegar should be clear and stable; it must have a fine, matured taste and volatile acidity of less than 4% (v/v) as acetic acid (Wealth of India, 1976). Further, brewed vinegar should have less than 0.1% of ethyl alcohol. The PFA (1954) requires the solid content of not more than 1.5% (w/v) and an ash content of 0.18%. Reference may also be made of the starter cultures used in the industry. Saccharomyces cerevisiae var. ellipsoides is used for rapid growth and high alcohol production for fruit juices; Saccharomyces cerevisiae group is considered best for starchy materials (Lai et al.). The acetic acid bacteria are obtained from mother vinegar as starters. The mother vinegar is obtained from static fermentation (3-4% acidity) of alcoholic ferment in a shallow vessel and is mixed in the ratio of 1:2 to 1:3 to have an initial acidity of over 1.0% (Bhadra and Gosh, 1982). The composition of the strains in the mother vinegar may be single or several belonging to the following species, Acetobacter acetii, A. xylinum, A. xylinoides etc. The choice of the strain is important, since some strains have the capacity to oxidize acetic acid itself to carbon dioxide and water. Reference may be, made to a Japanese patent (JP 06133756A2) wherein onion vinegar is prepared by initial aging of crude fermented product at 5-10 °C for 2-4 weeks and subsequent fermentation by a stationary process. The vinegar produced is made free from the unpleasant smell of conventional vinegar. Although onions and garlic are used very commonly to achieve seasoning effects and condiments as well as certain health derived benefits, the drawback has been that no vinegar preparation from onion in a shorter period exists, which combines the characteristics of flavour of onion and traditional vinegar. The main object of the present invention is a process for the preparation of brewed vinegar from onion. Another object of the present invention is to prepare the alcoholic ferment from onion bulbs using the yeast culture. Still another object of the present invention is to oxidize the alcoholic ferment of onion to acetic acid under static and accelerated conditions. Yet another object of the present invention is to increase the acceptability and nutritional status of onion by preparing vinegar from this base material as well as enlarge the product profile of vinegar obtained from natural substrates. Accordingly, the present invention provides an improved process for the preparation of brewed vinegar from onion, which comprises, (i) descaling manually or mechanically the outer dried scales of the bulbs, (ii) cleaning of desacaled bulbs using potable quality water for the removal of cross-contaminants and other extraneous matter, (iii) slicing of descaled and cleaned onion bulbs so as to facilitate pulping (iv) pulping of the onion slices by using a mechanical device, (v) extracting the juice enzymatically from the pulp and inactivating the enzyme by heat treatment for a period of 20-40 minutes, (iv) preparing an alcoholic fermentation of extracted onion juice by using a facultative microorganism for 5-6 days by incubation at 28-34°C and converting the alcohol to acetic acid by a strict aerobic microorganism at 28-35°C for 4 - 5 weeks to obtain the desired brewed vinegar of 4-5% acetic acid and the characteristic flavour of onion. In an embodiment of the present invention the onion type used is selected from white, red and small red. In an another embodiment of the present invention the enzyme used for enzymatic extraction is pectinase enzyme. In an another embodiment of the present invention the alcoholic fermentation of the extracted onion juice is effected by a strain of Saccharomyces cerevisiae In an another embodiment of the present invention a cell density of 2 x 108 CFU/ml, Saccharomyces cerevisiae is used to achieve the alcoholic fermentation of onion juice. In an another embodiment of the present invention the oxidization of alcoholic ferment to acetic acid is effected by Acetobacter sp. The novelty in the present invention relates to the critical control points protecting the flavour as well as overcoming the inhibition in the substrate for ethanolic fermentation by yeast and production of acetic acid by Acetobacter, together with preserving of natural colour and flavour of onion in vinegar. The following examples are given by way of illustration of the present invention and therefore should not be construed to limit the scope of the present invention. EXAMPLE-1 This example illustrates the use of white onion for onion vinegar production. Initially, 2 kg of white onion is used to produce alcohol. The weight of onions after cleaning and cutting is 1 .55 kg. From this 960 ml of onion juice is obtained by way of grinding in a blender jar and the resultant extract is treated with aliquots of 0.05 ml / 1 of commercial preparation of pectinase enzyme and squeezing by cheesecloth. The initial pH, total solids (°brix), total sugar contents (%) and reducing sugar (%) of onion juice is inoculated with Saccharomyces culture at level of 2 X 108 CFU/ml, onion juice and incubated at 32°C for a period of 10 days The changes that occurred in the physico-chemical parameters during the fermentation are given in Table 1 . The alcohol content of white onion ferment is 4.6 %. The acidity of final ferment dropped to 4.3 at the end of fermentation period. Table 1. Alcohol fermentation from white onion. (Table Removed) EXAMPLE-2 This example illustrates the use of small onion for onion vinegar production. Initially, 2 kg of small onion is used to produce alcohol. The weight of onions after cleaning and cutting is 1.46 kg. From this 1000 ml of onion juice is obtained by way of grinding in a blender jar and the resultant extract is treated with aliquots of 0.05 ml / I of commercial preparation of pectinase enzyme and squeezing by cheese-cloth. The initial pH, total solids fbrix), total sugar contents (%) and reducing sugar (%) of onion juice is inoculated with Saccharomyces culture at level of 2 X 108 CFU/ml, onion juice and incubated at 32°C for a period of 10 days The changes that occurred in the physico-chemical parameters during the fermentation are given in Table 2. The alcohol content of small onion ferment is 5.43 %. The acidity of final ferment dropped to 4.71 at the end of fermentation period. Table 2. Alcohol fermentation from small onion. (Table Removed) EXAMPLE-3 This example illustrates the use of red onion for onion vinegar production. Initially, 2 kg of red onion is used to produce alcohol. The weight of onions after cleaning and cutting is 1.8 kg. From this 1230 ml of onion juice is obtained by way of grinding in a blender jar, the resultant extract is treated with aliquots of 0.05 ml /1 of commercial preparation of pectinase enzyme and squeezing by cheese-cloth. The initial pH, total solids (°brix), total sugar contents (%) and reducing sugar (%) of onion juice is inoculated with Saccharomyces culture at level of 2 X 108 CFU/ml, onion juice and incubated at 32°C for a period of 10 days .The changes that occurred in the physico-chemical parameters during the fermentation are given in Table 3. The alcohol content of red onion ferment is 4.65 %. The acidity of final ferment dropped to 3.75 at the end of fermentation period. Table 3. Alcohol fermentation from red onion. (Table Removed) EXAMPLE-4 This example illustrates the acidification of alcohol ferment obtained from red onion under shake flask condition. The alcohol ferment obtained in the first stage, in aliquots of 200 ml each is subjected to acetification by inoculation with Acetobacter acetii. The contents of the flask are incubated at 32°C in a shaker maintained at 140 rpm. Periodically, acidity levels are analyzed. The results of this stage are presented in Table 4. The titratable acidity, expressed as acetic acid is 5.3% after 30 days of fermentation. Table 4. Acetification of alcoholic ferment obtained from red onion (under shake flask) (Table Removed) EXAMPLE- 5 This example illustrates the acidification of alcohol ferment obtained from small onion under shake flask condition. The alcohol ferment obtained in the first stage, in aliquots of 200 ml each is subjected to acetification by inoculation with Acetobacter acetii. The contents of the flask are incubated at 32°C in a shaker maintained at 140 rpm. Periodically, acidity levels are analyzed. The results of this stage are presented in Table 5. The titratable acidity, expressed as acetic acid is 4.15% in 30 days of fermentation. Table 5. Acetification of alcoholic ferment obtained from small onion (under shake flask) (Table Removed) The main advantages of present invention are: 1. Value addition to onion in obtaining naturally brewed vinegar with the characteristic flavour of onion and acetic acid. 2. The use of different onion varieties for preparing the alcoholic ferment by using simple and easier process steps. 3. Optimization of process condition for obtaining a final product of onion vinegar with 4-6% acetic acid. We claim: 1 . An improved process for the preparation of brewed vinegar from onion, which comprises, (i) descaling manually or mechanically the outer dried scales of the bulbs, (ii) cleaning of desacaled bulbs using potable quality water for the removal of cross-contaminants and other extraneous matter, (iii) slicing of descaled and cleaned onion bulbs so as to facilitate characterized in that pulping (iv) pulping of the onion slices by using a mechanical device, (v) extracting the juice enzymatically from the pulp and inactivating the enzyme) by heat treatment for a period of 20-40 minutes, (iv) preparing an alcoholic fermentation of extracted onion juice by using a facultative microorganism for 5-6 days by incubation at 28-34o C and converting the alcohol to acetic acid by a strict aerobic microorganismselected frp, Acetobacter sp.at 28-35°C for 4 -5 weeks to obtain the desired brewed vinegar of 4-5% acetic acid and the characteristic flavour of onion. 2. An improved process as claimed in claim 1, wherein the onion type used is selected from white, red and small red. 3. An improved process as claimed in claims 1 & 2, wherein enzyme used for enzymatic extraction is pectinase enzyme. 4. An improved process as claimed in claims 1-3, wherein the alcoholic fermentation of the extracted onion juice is effected by a strain of Saccharomyces cerevisiae 5. An improved process as claimed in claims 1-4, wherein a cell density of 2 x 108 CFU/ml,i Saccharomyces cerev:siae)\s used to achieve the alcoholic fermentation of onion juice. 6.; An improved process as claimed in claims 1-5, wherein the oxidization of alcoholic ferment to acetic acid is effected by Acetobacter acetii 7. An improved process for the preparation of brewed vinegar from onion substantially as herein described with reference to the examples.

Documents:

416-del-2001-abstract.pdf

416-del-2001-claims.pdf

416-del-2001-correspondence-others.pdf

416-del-2001-correspondence-po.pdf

416-del-2001-description (complete).pdf

416-del-2001-form-1.pdf

416-del-2001-form-18.pdf

416-del-2001-form-2.pdf

416-del-2001-form-3.pdf