Process for production of alcoholic beverages

Abstract: A process for production of an alcoholic beverage which is obtained by alcoholic fermentation by yeast, characterized by employing phospholipase which acts on fermentable materials prior to fermentation, to improve the flavor of alcoholic beverage. The phospholipase acts to reduce the bad influence of unsaturated fatty acids on the yeast.

Description: The present invention is concerned with processes for production of alcoholic beverages which are obtained by alcoholic fermentation by yeast, in particular, with improving the flavor of alcoholic beverage by employing phospholipase during the production process. Known processes for the production of alcoholic beverages by employing starchy material have included processes in which the starchy material is saccharified and solid-liquid separation is then conducted to prepare a fermentable liquid in many cases, whereupon the fermentable liquid is fermented by yeast as in the case of manufacturing whisky or beer. In other known processes, concurrent saccharification of starchy material and fermentation of fermentable material by yeast are carried out with mold rice "koji" or enzyme and yeast, e.g. when manufacturing Japanese "sake" or the Japanese distilled spirit "shochu". For production of alcoholic beverages employing starting materials containing sugar, the starting materials are prepared as fermentable liquid and the liquid is fermented by yeast e.g. when manufacturing wine or cider. In these processes, the flavor of the alcoholic beverages results mostly from ester formation by yeast during the fermentation. However, rice and other starting materials for alcoholic beverages, especially barley, wheat, rye, corn, etc. contain relatively large amounts of lipids, and it is known that unsaturated fatty acids in these lipids inhibit the ester formation by yeast. Accordingly, various methods for the removal of unsaturated fatty acids have been proposed as a way of improving the flavor of alcoholic beverages. There is employed, for example, a method for filtering mash. According to this method, though the amount of unsaturated fatty acids can be reduced to some extent, it is impossible to reduce the amount of unsaturated fatty acids to such a degree that the increase of flavor components can be expected. In the manufacture of Japanese "sake" or "shochu", the amount of unsaturated fatty acids can be reduced by steaming the raw material. According to this method, although the unsaturated fatty acids in the outer layers of cereal grains are removed, those in the inner parts of the grains cannot be removed and the complex lipids consisting mainly of fatty acids are reduced in quantity only by 10 and several percent. In the manufacture of Japanese "sake" or "shochu", a method wherein the polishing rate of raw material is increased has also been used, but it is not necessarily an economic method and even if the polishing rate of raw material is increased, unsaturated fatty acids in the inner parts of cereal grains cannot be removed, and the method is not efficient when a raw material contains a relatively large amount of lipids. JP-A-58/35674 describes a process for manufacturing Japanese "sake" rich in flavor in which the starting material, rice, is steeped in water to which lipase is added to free the fatty acids and then the steeped rice is steamed to remove the thus free fatty acids, especially unsaturated fatty acids. In JP-A-62/111695 (European Patent Publication No. 0219269), there is described a process for manufacturing starch syrup by employing phospholipase. The purpose of this process is the improvement of filterability, lowering of foam-formation, clarity of filtrate, etc., and there is no suggestion at all as to whether that technique might be utilized for the manufacture of alcoholic beverages. In JP-B-59/21594, there is described a process for manufacturing "shochu" by employing various enzyme preparations including amylase, protease and cellulose. The purpose of this process is the simplification of the process and the improvement of "shochu". In JP-A-62/55069, there is described a process for manufacturing alcoholic beverages obtained by alcoholic fermentation by yeast, in which corn grits are treated with amylase, protease and lipase. However, no process for the manufacture of alcoholic beverages employing phospholipase has been known. The present invention relates to a novel way of manufacturing an alcoholic beverage employing phospholipase in order to reduce the amount of unsaturated fatty acids during fermentation. In a particular aspect, the present invention relates to a process for production of an alcoholic beverage obtained by alcoholic fermentation by yeast, characterized by employing phospholipase which acts on fermentable material prior to fermentation. Rice, barley, wheat, rye, corn and the like, as starting materials for alcoholic beverages, contain unsaturated fatty acids in a free form or in the form of a glyceride, and unsaturated fatty acids inhibit the synthesis of esters by yeast during fermentation. Lipase frees the unsaturated fatty acids from glyceride when lipase is present during saccharification or fermentation. On the other hand, such starting materials as mentioned above contain phospholipids such as lecithin and lysolecithin, and these phospholipids, which are usually incorporated in the structure of starch, are freed as saccharification progresses and function as natural surface active agents owing to their amphiphatic nature. The present inventors have examined minutely the behaviors of unsaturated fatty acids and phospholipids during saccharification and fermentation in the manufacture of alcoholic beverages and found the following facts. The above phospholipids facilitate the dispersion of the unsaturated fatty acids into the liquid fraction and thereby facilitate the action of unsaturated fatty acids on yeast, but when phospholipase is added the phospholipase acts with phospholipids and the liberated unsaturated fatty acids are adsorbed to the solid fraction in fermentable material, whereby they are converted to a form which has less effect on yeast. The formation of flavor esters with by yeast is thereby promoted. Where further solid-liquid separation is conducted after saccharification, the unsaturated fatty acids are removed together with the solid fraction, so that efficiency may be improved. The present invention may be applied to the manufacture of various kinds of alcoholic beverages such as Japanese "sake", beer, whisky, Japanese distilled spirit "shochu", spirits, wine, brandy and cider, and may be applied to various kinds of starting materials such as rice, barley, wheat, rye, corn, maize, oat, potato, sweet potato, grape, apple, sugar cane and the like. The present invention is effective especially for starting materials which contain a large amount of unsaturated fatty acid, such as barley, wheat, rye and corn. In working the present invention, it may not be necessary to make modifications in the conventional manufacturing processes for various kinds of alcoholic beverages. It may suffice if phospholipase is added at an appropriate stage of the conventional process. The solid-liquid separation before fermentation, which is more efficient for this invention, is carried out in most conventional manufacturing process for production of alcoholic beverages. In the manufacture of e.g. beer, malt is produced from barley and milled, and warm water and optional cereal adjuncts are added to the thus-milled malt to saccharify it, following which the mash is filtered. Hops are added to the filtered wort and the wort is boiled, whereupon the fermentation of the wort is carried out after the wort has been cooled. By contrast, in the manufacture of grain whisky, corns are cooked with water, and ground malt as enzyme-providing agent is added to the thus-cooked corns to saccharify, after which fermentation of the mash by yeast is carried out without filtration prior to fermentation. The former process is a representative example of the cases where fermentation is carried out after filtration, which removes the solid fraction from saccharified material, and the latter is a representative example of the cases where fermentation is carried out without removing solids from saccharified mash. The foregoing are the outlines of the examples of manufacturing processes of alcoholic beverages, to which the present invention may be applied, and further to the manufactures of Japanese "sake", Japanese distilled spirit "shochu", spirits, fruit wines, brandies and cider, in which preferably these methods may be applied without making any modifications in each of the widely known processes. Phospholipase may be added before the commencement of saccharification, e.g. together with a saccharifying enzyme-providing agent. It can also be added to fermentable material after the commencement of saccharification. As phospholipase retains its activity even at a relatively high temperature and functions within a relatively wide pH range and temperature range, the pH value and temperature of fermentable material do not need to be adjusted for the function of phospholipase, and usual alcoholic beverage-manufacturing conditions are sufficient for this purpose. Phospholipase can also be added after the completion of saccharification and act for a desired time. Phospholipase can be added to fermentable material prior to fermentation and acts for a desired time, in the process for production of alcoholic beverages employing sugar in starting material e.g. fruit juice. At whichever point of time of the above stages phospholipase may be added, the time during which phospholipase acts should be sufficient for the phospholipids in the fermentable material to decompose sufficiently, and though such time varies depending upon the conditions such as the amounts of employed phospholipase, content of phospholipids, pH value, temperature etc., it may be e.g. 2 hours at a temperature of 60°C. If phospholipase is added before the commencement of saccharification, it may function well during the saccharification, so that this method is convenient. In fermentable material, unsaturated fatty acids are dispersed. The unsaturated fatty acids are adsorbed to the solid fraction in the fermentable material and insolubilized by the action of phospholipase, so it become difficult for these to act on yeast. Further, when the fermentable material is subject to solid-liquid separation by conventional means such as filtration and centrifugal separation, the unsaturated fatty acids adsorbed to the solid fraction are removed. The formation of esters by yeast is greatly inhibited by the presence of unsaturated fatty acids in a concentration of 100 ppm or more, and when the concentration of unsaturated fatty acids is below 100 ppm, the amounts of esters formed increase with the decrease in the amounts of unsaturated fatty acids, and it is desirable that the amount of the unsaturated fatty acids is below 50 ppm. By the above action of the phospholipase on unsaturated fatty acids, the concentration of unsaturated fatty acids in the liquid fraction may be reducible below 50 ppm. Furthermore a fermentable material, the concentration of unsaturated fatty acids of which has been below 50 ppm, can be obtained by subjecting the fermentable material to solid-liquid separation. In the concurrence of saccharification and fermentation for manufacturing alcoholic beverages e.g. the manufacturing process of Japanese "sake", steamed rice, mold rice "koji", yeast and water are mixed and the thus obtained mixture is carried out to saccharification and fermentation at the same time. In this case, phospholipase may be added at the commencement of saccharification fermentation (the first addition of material), or after that time, e.g. at the time of second addition of the material. Though the amount of phospholipase to be added depend upon the amounts of phospholipids in the fermentable material, the amount of unsaturated fatty acids, the nature of the starting material, the temperature while phospholipase acts, pH value, time etc., it is e.g. 2.5 to 26 U/ℓ mash for manufacturing grain whisky, 2.5 to 25 U/ℓ wort for manufacturing beer, 25 to 50 U/ℓ mash for manufacturing Japanese "sake", 10 to 25 U/ℓ mash for manufacturing "shochu". In the present invention, the activity of phospholipase is defined so the amount of enzyme capable of decomposing yolk lysophosphatidyl choline (L P C) at a rate of 1 micromole/min at pH value of 5.5 and at a temperature of 40°C is 1 unit (U). Though any phospholipase may be employed, phospholipase B is particularly desirable. As phospholipase, the ones produced by microorganisms such as Aspergillus , Rhizopus , Penicillium , Candida , Corticium, Bacillus are suitable. Though it is preferable to employ purified enzyme as the enzyme preparation, crude enzyme may also be employed provided that the quality of alcoholic beverage is acceptable. Various kinds of phospholipase products are commercially available and these may be employed in the manufacture of alcoholic beverages. Even the products commercially available as "lipase preparation" may also be employed, if such products contain phospholipase. Furthermore, cultures of microorganisms e.g. phospholipase-containing products called "solid koji" may also be employed. In the following, the present invention is explained more concretely with reference to Examples. Example 1 5.7 kg of barley was milled, 26.4ℓ of water was added to the milled barley, and the resulting mixture was cooked for 30 min at a temperature of 120°C. Amylase in an amount of 2300 U/ℓ and phospholipase B in an amount of 20 U/ℓ were added to the prepared cooked barley mash, and the resulting mixture was saccharified at a pH of 5.5 at a temperature of 60°C and filtered by filter paper. The amounts of unsaturated fatty acids in the filtrate were measured. The addition of phospholipase B was conducted at the commencement of the saccharification or 2 hours after the commencement of saccharification, and the actioning times after the addition of phospholipase B were selected within the range from 0 to 4 hours. As control, an experiment was carried out following a procedure as above but wherein no phospholipase was added. The result is set forth in the following Table 1. Phospholipase added Time after the addition of phospholipase (hr) Concentration of unsaturated fatty acid (C 18") (ppm) At the commencement of saccharification 0 2.4 1 9.7 2 5.7 4 2.5 2 hours after the commencement of saccharification 0 67.6 1 30.1 2 30.3 Phospholipase not added (4 hours after the commencement of saccharification) 120 Example 2 A. 5.7 kg of barley was milled and 26.4 ℓ of water added thereto, following which the resulting dispersion was cooked for 30 min at a temperature of 120°C. After the cooked mash had been cooled to a temperature of 60°C, 70000 U of glucoamylase and 600 U of phospholipase were added thereto and the mash was saccharified for 120 min at a temperature of 60°C. Yeast was added to 16 ℓ of filtrate obtained by filtering the saccharified mash with filter paper and the filtrate was fermented at a temperature of 30°C for 7 days, whereupon it was distilled. As control, the same procedure was conducted without employing phospholipase enzyme. The change in the amount of linoleic acid (C 18") caused by the procedure and the amounts of esters after distillation were determined by gas chromatography, and the result set forth in Table 2 was obtained. Furthermore the amount of linoleic acid (C 18") in the supernatant liquid obtained from fermented mash, using centrifugal separation as a solid-liquid separation technique, was determined and the result set forth in Table 2 was obtained. Phospholipase Added Phospholipase not added C 18" after cooking 2 ppm 2 ppm C 18" in the mash after saccharification 1064 872 C 18" in the filtrate after saccharification 9 93 C 18" in the centrifuged supernatant liquid after saccharification 29 106 Amounts of esters after distillation EtC 2 174 % 100 % EtC 8 136 % 100 % EtC 10 200 % 100 % EtC 12 500 % 100 % B. Procedure up to the saccharification was carried out in the same way as A, and solid-liquid separation was carried out by machine filter in place of filter paper. Subsequently, fermentation and distillation were carried out in the same way as in A, and the amount of linoleic acid (C 18") in the distillate was determined. The obtained result is set forth in Table 3. C 18" in the filtrate after saccharification 12 ppm Amounts of esters after distillation EtC 2 176 % (*) EtC 8 175 % EtC 10 240 % EtC 12 650 % The above result may be compared with the result obtained when phospholipase was not added, as set forth in Table 2, as control. C. Cooking was carried out in the same way as A, and then the cooked mash was cooled to a temperature of 60°C, following which 2.5 kg of mold barley as phospholipase source, 10 ℓ of water and 1000 U of glucoamylase were added to the cooked mash. The resulting mixture was saccharified, and then solid-liquid separation, fermentation and distillation were carried out in the same way as A. The result as set forth in the following Table 4 was obtained. C 18" in the Filtrate after saccharification 4 ppm Amounts of esters after distillation EtC 2 294 % (*) EtC 8 300 % EtC 10 427 % EtC 12 700 % The above result, may be compared with the control result obtained when phospholipase was not added, as set forth in Table 2.

Claims: A process for producing an alcoholic beverage which is obtained by alcoholic fermentation by yeast, characterised by the employment of a phospholipase to act on fermentable materials. A process according to claim 1 wherein the starting materials are saccharified and the phospholipase is added before, during or after saccharification wherein the phospholipase acts prior to the fermentation. A process according to claim 1 in which fermentation occurs concurrently with saccharification of starting materials, the phospholipase being added before or during the saccharification-fermentation process. A process according to claim 1 in which sugar is fermented in the starting materials and the phospholipase is added before fermentation starts. A process according to claim 1, 2, 3 or 4, wherein the process includes solid-liquid separation prior to fermentation when phospholipase acts on fermentable materials. A process according to claim 1, 2, 3 or 4, wherein the process includes distilling. A process according to claim 1, 2, or 3, wherein the starting material is at least one selected from rice, barley, wheat, rye, corn, maize, oat, potato and sweetpotato. A process according to claim 1 or 4, wherein the starting material is at least one selected from grape, apple and sugar cane. Use of phospholipase, in a process of preparing and fermenting materials for making an alcoholic beverage, to reduce the action of fatty acids on yeast in the fermentation process.

Inventors: SATO KENJI, TORII KAZUYUKI, SATO, KENJI, TORII, KAZUYUKI
Applicants: SUNTORY LTD, SUNTORY LIMITED
Application year: 1991
Main classification: C12G3
IPC codes: C12C5, C12G3, C12C7, C12N9, C12G1