first , the abovementioned component ( a ) used in the present invention shall be described . the diglycerol monoesters of fatty acids used in the present invention can be obtained by preparing an ester mixture through esterification of diglycerol monoesters of fatty acids and fatty acids , transesterification of diglycerol monoesters of fatty acids and fatty acids and methyl esters of fatty acids or other esters , esterification of glycerol by fatty acid halides , etc . and then performing separation and purification by a method such as distillation fractionation , adsorption chromatography separation , liquid - liquid extraction separation , etc . diglycerol monoesters of fatty acids suitable for the present purpose can usually be obtained efficiently and economically by the molecular distillation method . however , the present invention is not limited to these methods . the constituent fatty acids of the diglycerol monoesters of fatty acids to be used in the milk - constituent - containing beverage by the present invention are mainly comprised of myristic acid and / or palmitic acid , the total amount of which comprises 70 wt .% or more and preferably 90 wt .% or more of the constituent fatty acids . it is unfavorable for the total amount to be less than 70 wt .% since the effect of suppressing the germination of spores of and proliferation heat - resistant spore - forming bacteria will be inadequate in this case . the monoester content of the ester mixture in the diglycerol monoesters of fatty acids used in the present invention is 70 wt % or more and preferably 80 wt % or more . it is unfavorable for the monoester content to be less than 70 wt % since the effect of suppressing the germination of spores of and proliferation heatresistant spore - forming bacteria will be inadequate in this case . the diglycerol monoesters of fatty acids used in the present invention may be added directly to the milk - constituent - containing beverage or may be added by mixing in the water or milk - constituent that comprises the milk - constituent - containing beverage . the added amount of the diglycerol monoesters of fatty acids used in the present invention is 0 . 01 to 1 . 0 wt .% or preferably 0 . 01 to 0 . 5 wt % to 1 part of milk - constituent - containing beverage . if the added amount is less than 0 . 01 wt .%, the effect of suppressing the germination of spores of and proliferation heat - resistant spore - forming bacteria will be inadequate , and if the added amount is greater than 1 . 0 wt .%, there will be an undesirable effect on the flavor . the abovementioned component ( b ) used in the present invention shall be described next . the citric acid esters of mono - and diglycerides of fatty acids , succinic acid esters of mono - and diglycerides of fatty acids , or diacetytartaric acid esters of mono - and diglycerides of fatty acids used in the present invention is a mixed ester of ( a ) glycerol , ( b ) fatty acids , and ( c ) citric acid , succinic acid , or diacetyl tartaric acid , and the fatty acid constituents of the ester are saturated and / or unsaturated fatty acids with 12 to 22 carbons . the polyglycerin monoesters of fatty acids used in the present invention is an ester of polyglycerol and fatty acids , and is preferably an ester of polyglycerol with an average degree of polymerization of 3 or more and saturated and / or unsaturated fatty acids with 12 to 22 carbons . the polyglycerin monoester of fatty acids has an hlb of 3 to 16 . the sucrose esters of fatty acids to be used in the present invention is an esterification product of sucrose and fatty acids , and though the fatty acids thereof can be saturated and / or unsaturated fatty acids with 12 to 22 carbons , it is especially preferable for the fatty acids to be saturated fatty acids . the sucrose esters of fatty acids have an hlb of 3 to 16 . as component ( b ) of the present invention , one or more esters is selected from among a group comprised of citric acid esters of mono - and diglycerides of fatty acids , succinic acid esters of mono - and diglycerides of fatty acids , diacetyltartaric acid esters of mono - and diglycerides of fatty acids , polyglycerin monoester of fatty acids with an hlb of 3 to 16 , and sucrose fatty acid esters with an hlb of 3 to 16 . the total amount of component ( b ) added to the milk - constituent - containing beverage is 0 . 002 to 0 . 3 wt % and preferably 0 . 01 to 0 . 15 wt % . with an added amount of less than 0 . 002 wt % , the purported effects of preventing coagulation , oiling off , feathering , precipitation , etc . of milk constituents cannot be exhibited satisfactorily . an added amount of more than 0 . 3 wt % not only brings about an undesirable effect on the flavor and taste but is also uneconomical since the purported effects will not be improved . by containing ( a ) diglycerol monoesters of fatty acids and ( b ) at least one emulsifier selected from a group comprised of citric acid esters of mono - and diglycerides of fatty acids , succinic acid esters of mono - and diglycerides of fatty acids , diacetyltartaric acid esters of fatty acids , polyglycerin monoesters of fatty acids with an hlb of 3 to 16 , and sucrose esters of fatty acids with an hlb of 3 to 16 , the milk - constituent - containing beverage of the present invention becomes a beverage with good storage properties in which the germination of spores of and proliferation heat - resistant spore - forming bacteria are suppressed , flat sour deterioration is prevented , coagulation , oiling off , feathering , precipitation , etc . of the milk constituents will not occur , and the flavor and taste will not be damaged even when the beyerage is stored under high temperature over long periods of time . as long as the milk - constituent - containing beverage of the present invention contains the emulsifier ( a ) and the emulsifier ( b ) used in the present invention , emulsifiers besides those used in the invention may be used within quantiry ranges which will not damage the effects of the invention . the milk - constituent - containing beverage of the present invention shall now be described by way of examples and comparison examples . 4 kg of coffee bean extract , 0 . 8 kg of granulated sugar , 4 kg of raw milk were mixed to make a coffee - milk beverage . a total of 15 g of the emulsifiers shown in table 1 where then added ( milk fat content : 1 . 5 %) to this coffee - milk beverage . after preliminary emulsification , the drink was homogenized at 150 kg / cm 2 with a piston homogenizer . forty 250 ml of the coffee - milk beverage were then dispensed into each 40 test vessels . and 1 ml of a spore suspension ( b . stearothermophilus , concentration : 1 × 10 4 spores / ml ) was added to each test vessels . the test vessels were then heat sterilized for 1 minute at 121 ° c . and stored for 30 days at 55 ° c . the number of aliquots among the forty test vessels which had undergone deterioration or decomposition was then counted . the results are shown in tables 1 and 2 . at the same time , oiling off , feathering , precipitation , and neck ring were observed for the coffee - milk beverage test vessels which had not undergone deterioration due to the heat - resistant spore - forming bacteria . 7 . 6 kg of coffee bean extract , 600 g of granulated sugar , 960 ml of raw milk , 830 g of whole milk powder , and 10 g of sodium bicarbonate were mixed to make a coffee - milk drink . a total of 10 g of the emulsifiers shown in table 2 where then added ( milk fat content : 2 . 5 %) to this coffee - milk drink . after preliminary emulsification , the drink was homogenized at 150 kg / cm 2 with a piston homogenizer . forty 250 ml of the coffee - milkk beverage were then dispensed and 1 ml of a spore suspension ( c . thermoaceticum , concentration : 1 × 10 4 spores / ml ) was added to each test vessels . the test vessels were then heat sterilized for 20 minutes at 121 ° c . and stored for 30 days at 55 ° c . the number of test vessels among the forty test vessels which had undergone deterioration or decomposition was then counted . the results are shown in tables 3 and 4 . at the same time , oiling off , feathering , precipitation , and neck ring were observed for the coffee - milk beverage test vessels which had not undergone deterioration due to the heat - resistant spore - forming bacteria . table 1______________________________________types of emulsifier ( see note 2 ), figures in evaluation itemsex . the ( ) are the contents ( see note 1 ) no . ( wt . %). a b c d e______________________________________1 a1 ( 0 . 05 ) b1 ( 0 . 1 ) -- 0 ⊚ ⊚ ◯⊚ ⊚ 2 a1 ( 0 . 05 ) b1 ( 0 . 07 ) b2 ( 0 . 03 ) 0 ⊚ ⊚ ⊚ ⊚ 3 a2 ( 0 . 05 ) b3 ( 0 . 1 ) -- 0 ◯⊚ ⊚ ◯⊚ ⊚ 4 a2 ( 0 . 05 ) b4 ( 0 . 1 ) -- 0 ◯⊚ ◯⊚ ◯⊚ ◯. circleincirc le . 5 a3 ( 0 . 05 ) b5 ( 0 . 1 ) -- 0 ⊚ ◯ ⊚ ⊚ 6 a4 ( 0 . 05 ) b1 ( 0 . 1 ) -- 0 ⊚ ⊚ ⊚ ⊚ ______________________________________ note 1 : evaluation items a = number of test vessels among the 40 test vessels that underwent deterioration , b = feathering , c = oiling off , d = precipitation , and e = neck ring , the following evaluation standards were used . when two symbols are indicated , this means that the condition is intermediate those corresponding to the two symbols . ⊚ = unobserved , ◯ = observed slightly , □ = observed clearly but in small quantities , δ = observed in large quantities and x = impossible to evaluate . note 2 : types of emulsifier a1 diglycerol monoesters of fatty acids constituent fatty acids : palmitic acid 99 wt . % monoester content : 85 wt . % a2 diglycerol monoesters of fatty acids constituent fatty acids : myristic acid 99 wt . % monoester content : 80 wt . % a3 diglycerol monoesters of fatty acids constituent fatty acids : myristic acid 99 wt . % monoester content : 85 wt . % a4 diglycerol monoesters of fatty acids constituent fatty acids : palmitic acid 55 wt . % myristic acid 45 wt . % monoester content : 80 wt . % b1 diacetyltartaric acid esters of monoand diglycerides of fatty acids ( used poem w10 made by riken vitamin co .) constituent fatty acids : steari acid 70 wt . %, palmitic acid 30 wt . % b2 polyglycerin monoesters of fatty acids ( used poem j0381 made by riken vitamin co .) constituent fatty acids : oleic acid 80 wt . % hlb : 12 b3 succinic acid esters of monoand diglycerides of fatty acids ( used poem b10 made by riken vitamin co .) constituent fatty acids : stearic acid 70 wt . %, palmitic acid 30 wt . % b4 citric acid esters of monoand diglycerides of fatty acids ( used poem k30 made by riken vitamin co .) constituent fatty acids : stearic acid 70 wt . %, palmitic acid 30 wt . % b5 sucrose esters of fatty acids ( used ryoto s1570 made by mitsubishi chemical corp .) constituent fatty acids : stearic acid 70 wt . % hlb : 15 table 2______________________________________com - par - ison types of emulsifier evaluation itemsex . ( see note 4 , figures in the ( see note 3 ) no . ( ) are the contents ( wt . %). a b c d e______________________________________1 a1 ( 0 . 05 ) b &# 39 ; 11 ( 0 . 1 ) -- 0 δ □ ◯ □◯ □ 2 a1 ( 0 . 05 ) b &# 39 ; 12 ( 0 . 1 ) -- 0 □ ◯⊚ □ ◯ 3 a1 ( 0 . 05 ) b &# 39 ; 13 ( 0 . 1 ) 0 □ ◯ □ □ 4 a &# 39 ; 11 ( 0 . 05 ) b1 ( 0 . 1 ) -- 14 ⊚ ⊚ ◯⊚ ⊚ 5 a &# 39 ; 12 ( 0 . 05 ) b &# 39 ; 13 ( 0 . 03 ) b &# 39 ; 14 21 δ □ □ □◯ δ ( 0 . 07 ) 6 a &# 39 ; 13 ( 0 . 05 ) b &# 39 ; 11 ( 0 . 1 ) -- 10 δ □ ◯ □ δ □ 7 a &# 39 ; 14 ( 0 . 05 ) b &# 39 ; 15 ( 0 . 1 ) -- 18 δ δ □ δ □ δ8 a &# 39 ; 15 ( 0 . 05 ) b1 ( 0 . 1 ) -- 40 x x x x9 -- b1 ( 0 . 1 ) b &# 39 ; 16 31 ◯⊚ ◯⊚ ⊚ ◯ ( 0 . 05 ) 10 -- b1 ( 0 . 1 ) b7 40 x x x x ( 0 . 05 ) 11 -- b1 ( 0 . 1 ) b8 37 ⊚ ⊚ ◯ ⊚ ( 0 . 05 ) 12 -- b1 ( 0 . 1 ) b9 40 x x x x ( 0 . 05 ) ______________________________________ note 3 : evaluation items , see note 1 of table 1 . note 4 : types of emulsifier a &# 39 ; 11 diglycerol monoesters of faty acids constituent fatty acids : lauric acid 99 wt . % monoester content : 90 wt . % a &# 39 ; 12 diglycerol monoesters of faty acids constituent fatty acids : oleic acid 99 wt . % monoester content : 90 wt . % a &# 39 ; 13 diglycerol monoesters of faty acids constituent fatty acids : palmiti acid 55 wt . % stearic acid 45 wt . % monoester content : 80 wt . % a &# 39 ; 14 diglycerol monoesters of faty acids constituent fatty acids : myristi acid 99 wt . % monoester content : 40 wt . % a &# 39 ; 15 diglycerol monoesters of faty acids constituent fatty acids : palmiti acid 45 wt . % stearic acid 55 wt . % monoester content : 35 wt . % b6 citric acid esters of monoand diglycerides of fatty acids constituent fatty acids : stearic acid 70 wt . %, palmitic acid 30 wt . % b &# 39 ; 11 lecithin ( used dx lecithin made by nisshin seiu co .) b &# 39 ; 12 sorbitan esters of fatty acids ( used poem s300b made by riken vitami co ., ltd .) constituent fatty acids : stearic acid 70 wt . %, palmitic acid 30 wt . % b &# 39 ; 13 monoand diglycerides of fatty acids ( used emulseems made by riken vitamin co ., ltd .) constituent fatty acids : stearic acid 70 wt . %, palmitic acid 30 wt . % b &# 39 ; 14 polyglycerin monoesters of fatty acids ( used poem j0080 made by rike vitamin co ., ltd .) constituent fatty acids : stearic acid 70 wt . %, palmitic acid 30 wt . % b &# 39 ; 15 polyglycerol esters of polycondensed ricinoleic acid . ( used poem pr300 made by riken vitamin co ., ltd .) hlb : 0 . 3 b &# 39 ; 16 polyglycerin monoesters of fatty acids ( used poem j0021 made by rike vitamin co ., ltd .) constituent fatty acids : lauric acid 99 wt . % hlb : 15 b7 polyglycerin monoesters of fatty acids ( used poem j0041 made by riken vitamin co ., ltd .) constituent fatty acids : myristic acid 99 wt . % hlb : 1 b8 sucrose esters of fatty acids ( used ryoto p1670 made by mitsubishi chemical corp .) constituent fatty acids : palmitic acid 80 wt . % hlb 16 table 3______________________________________types of emulsifier evaluation items ( see note 6 ), figures in ( see note 5 ) ex . no . the ( ) are the contents ( wt . %). a b c d e______________________________________7 a2 ( 0 . 005 ) b1 ( 0 . 05 ) -- 0 ◯⊚ ⊚ ◯⊚ 6 ⊚ 8 a2 ( 0 . 005 ) b1 ( 0 . 035 ) b2 ( 0 . 015 ) 0 ⊚ ⊚ ⊚ ⊚ 9 a1 ( 0 . 05 ) b4 ( 0 . 05 ) 0 ⊚ ⊚ ◯⊚ ⊚ ______________________________________ note 5 : evaluation items , see note 1 of table 1 . note 6 : types of emulsifier , see note 2 of table 1 . table 4______________________________________compa - types of emulsifier evaluation itemsrison ( see note 4 ), figures in the ( see note 3 ) ex . no . ( ) are the contents ( wt . %). a b c d e______________________________________13 a1 ( 0 . 05 ) b &# 39 ; 21 ( 0 . 05 ) -- 0 □ ◯ □◯ δ □ 14 a1 ( 0 . 05 ) b1 ( 0 . 035 ) b &# 39 ; 22 0 δ □ □◯ □ δ ( 0 . 015 ) 15 a &# 39 ; 16 ( 0 . 05 ) b1 ( 0 . 05 ) -- 16 ◯⊚ ⊚ ◯⊚ ◯. circleincirc le . 16 a &# 39 ; 17 ( 0 . 05 ) b &# 39 ; 23 ( 0 . 05 ) -- 9 δ □ □ □ δ17 a &# 39 ; 18 ( 0 . 05 ) b &# 39 ; 24 ( 0 . 05 ) -- 25 δ δ x δ18 -- b1 ( 0 . 05 ) b7 30 ◯ ⊚ ◯ ◯ ( 0 . 05 ) 19 -- b1 ( 0 . 05 ) bb9 5 ⊚ ◯⊚ ⊚ ⊚ ( 0 . 05 ) 20 a1 ( 0 . 05 ) b &# 39 ; 25 ( 0 . 05 ) -- 0 δ δ □ δ δ______________________________________ note 7 : evaluation items , see note 1 of table 1 . note 8 : types of emulsifier a &# 39 ; 16 diglycerol monoesters of fatty acids constituent fatty acids : lauric acid 99 wt . % monoester content : 90 wt . % a &# 39 ; 17 diglycerol monoesters of fatty acids constituent fatty acids : palmitic acid 55 wt . % stearic acid 45 wt . % monoester content : 70 wt . % a &# 39 ; 18 diglycerol monoesters of fatty acids constituent fatty acids : myristic acid 99 wt . % monoester content : 40 wt . % b &# 39 ; 21 lecithin ( used dx lecithin made by nisshin seiu co .) b &# 39 ; 22 monoand diglycerides of fatty acids ( used emulseehro made by riken vitamin co ., ltd .) constituent fatty acids : oleic acid 75 wt . % b &# 39 ; 23 lecithin ( used lecithin pk made by riken vitamin co .) b &# 39 ; 24 sucrose esters of fatty acids ( used ryoto er290 made by mitsubishi chemical corp .) constituent fatty acids : erucic acid 90 wt . % b &# 39 ; 25 propylen glycol esters of fatty acids ( used rikemul ps100 made by riken vitamin co .) constituent fatty acids : stearic acid 70 wt . %, palmitic acid 30 wt . % b9 sucrose esters of fatty acids ( used ryoto p1670 made by mitsubishi chemical corp .) constituent fatty acids : palmitic acid 80 wt . % hbl : 16 as the above , with the milk - constituent - containing beverage by the present invention , since the germination of spores of and proliferation heat - resistant spore - forming bacteria are suppressed , flat sour deterioration is prevented , and problems such as coagulation , oiling off , feathering , precipitation , neck ring , etc . of the milk constituents do not occur , the problems mentioned above are solved even for cases where the beverage is stored under heated conditions in a vending machine , etc .
the present invention is relating to milk - constituent - containing beverages which are preserved and distributed in metal cans , and characterized that a milk - constituent - containing beverage , which is provided with growth inhibition effects against heat - resistant spore - forming bacteria and in which such problems as coagulation , oiling off , feathering , precipitation , neck ring , etc . of the milk constituents are suppressed , said milk - constituent - containing beverage containing diglycerol monoesters of fatty acids and at least one emulsifier such as citric acid esters of mono - and diglycerides of fatty acids , guccinic acid esters of mono - and diglycerides of fatty acids , diacetyltartaric acid esters of mono - and diglycerides of fatty acids , polyglycerin monoesters of fatty acids with an hlb of 3 to 16 , and sucrose esters of fatty acids with an hlb of 3 to 16 , said beverage being characterized in that 70 wt . % or more of the fatty acid composition of the diglycerol monoesters of fatty acids is taken up by the total amount of myristic acid and / or palmitic acid and in that the monoester content of the ester compositioin of the diglycerin fatty acid monoester is 70 wt . % or more .