Soy Sauce and Traditional Local Dishes
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Greetings Soy Sauce and Traditional Local Dishes Regional Characteristics of Soy Sauce Identified by Analytical and Sensory Properties Hiroe Otomo and Miho Imamura, Research and Development Division, Kikkoman Corporation Tsutomu Sasaki, Product Development Division, Kikkoman Food Products Company Kunitomo Kizu, Production Division, Kikkoman Food Products Company I. Introduction which shows that salty soy sauce is favored in these Japanese soy sauce is defined under Japanese regions. In contrast, dashi soy sauce such as kombu Agricultural Standards (JAS) as koikuchi (common), (kelp) soy sauce tends to be favored in Hokkaido, while tamari (tamari), usukuchi (light-colored), saishikomi (re- low-sodium soy sauce is ranked as one of the more fermented), or shiro (extra-light-colored). In addition, popular products in Kinki, meaning salt concentration is there is a dashi soy sauce (soy sauce blended with dashi) lower in these regions. In Kyushu, soy sauce products that is sometimes used outside of the five types listed.1) generally have lower salt concentrations. (Figure 1) Among these five types, koikuchi accounts for roughly |:Range of values from minimum to maximum 80 percent of the soy sauce consumed in Japan, and is Salt Concentration (%) said to vary by region in terms of characteristics such as 20 1) saltiness and sweetness. Despite this widely held 18 perception, no report has yet scientifically examined 16 14 actual regional differences in soy sauces. Thus, for the 12 purpose of scientifically elucidating regional 10 characteristics of soy sauce, we conducted a component 8 6 analysis and sensory evaluation of soy sauces consumed 4 in individual regions throughout Japan. 2 0 Outlying Tokyo Hokkaido HokurikuTohoku Areas Metropolitan Chukyo Kinki ShikokuChugokuKyushu II. Component Analysis in Kanto Area To study the characteristics of soy sauce consumed in Figure 1 Mean salt concentration of the five bestselling products in each region each region, we prepared a list of soy sauce products [Sugar Concentration, Glycyrrhizin Concentration (Sweetness)] that sell well by region, and used the mean value of the Concentrations of major monosaccharides, sucrose (a top five products in each region as the component value disaccharide) and glycyrrhizin (the chief sweetness representing that region. The regions and the total constituent of licorice) contained in soy sauce were market share of the top five products in each region are measured to express sweetness in terms of glucose. The as follows: total converted values were then compared between Hokkaido (44.3%), Tohoku (41.7%), Hokuriku (26.9%), regions. The results showed that soy sauce used in Outlying Areas in Kanto (Kanto Region excluding the Kyushu was far sweeter than its counterparts in other Tokyo Metropolitan Area) (38.2%), Tokyo Metropolitan regions, with its sweetness value being almost double Area (Tokyo Metropolis and three neighboring that of soy sauce used in the second and subsequent prefectures) (44.2%), Chukyo (44.2%), Kinki (49.4%), regions. In terms of sweetness, Kyushu was followed by Chugoku (27.0%), Shikoku (40.9%), and Kyushu Chugoku and Shikoku, while the soy sauce in Tohoku, (19.1%). *We compiled samples based on data from the Outlying Areas in Kanto, the Tokyo Metropolitan Area, Nikkei POS Information Service (soy sauce category and Chukyo tended to have the least sweetness. (Figure 2) from 2011 to 2013, except for Hokuriku, for which we Glucose equivalent (%) used data from 2012 to 2013). 18 A general analysis of soy sauce usually examines the 16 total nitrogen, salt concentration and color, which are 14 referred to by the JAS. Although no particular trends by 12 region were found among these factors, except for salt 10 8 concentration, interesting trends were noted in 6 components related to the flavor of the soy sauce, such 4 as sweetness, brewed aroma (HEMF), and umami 2 0 (savory taste). Findings for these components, as well as Outlying Tokyo HokkaidoHokurikuTohoku Areas Metropolitan Chukyo Kinki ShikokuChugokuKyushu salt concentration, are outlined below. in Kanto Area Figure 2 Mean glucose equivalent of sweetness constituents [Salt Concentration (Saltiness)] concentrations in the five bestselling products in each region Soy sauce consumed in the Tokyo Metropolitan Area and [Levulinic Acid Concentration (Hydrolyzed Vegetable Protein)] Outlying Areas in Kanto has higher salt concentrations, Levulinic acid is a substance generated when sugar is FOOD CULTURE 3 Umami equivalent converted from nucleic acid and glutamic acid concentrations hydrolyzed with hydrochloric acid. As levulinic acid is 700 not found in brewed soy sauce (manufactured by 600 fermentation), it is used as a component to be analyzed 500 to determine whether a soy sauce contains hydrolyzed 400 vegetable protein. Levulinic acid content indicates that 300 soy sauce used in Hokuriku, Tohoku, Chugoku and Kyushu is manufactured by a mixing method or by a 200 semi-fermentation method. (Figure 3) 100 0 Outlying Tokyo Hokkaido HokurikuTohoku Areas Metropolitan Chukyo Kinki ShikokuChugokuKyushu Levulinic acid concentration (%) in Kanto Area 0.70 Figure 5 Umami equivalent converted from mean value of nucleic acid and 0.60 glutamic acid concentrations of the five bestselling products in each region 0.50 [Summary] 0.40 Hokkaido: The salt content is rather low and umami is 0.30 prominent, which is attributable to the prevalence of 0.20 dashi soy sauce. The brewed aroma is the most subdued 0.10 of all the regions. 0.00 Outlying Tokyo Tohoku: The salt content is high and sweetness is HokkaidoHokurikuTohoku Areas Metropolitan Chukyo Kinki ShikokuChugokuKyushu in Kanto Area subdued, while the hydrolyzed vegetable protein keeps Figure 3 Mean levulinic acid concentration of the five bestselling products in each region the umami rather prominent. Hokuriku: The salt content is high, umami is prominent, [HEMF Concentration (Brewed Aroma of Soy Sauce)] and sweetness is more prominent than in Kanto. In Hokuriku, Tohoku, Chugoku and Kyushu, where soy Outlying Areas in Kanto: The salt content is high, and sauce containing levulinic acid is favored, the soy sauce sweetness is subdued. Brewed soy sauce prevails. contains hydrolyzed vegetable protein, and the brewed Tokyo Metropolitan Area: The salt content is high, and soy sauce content is smaller. Therefore, soy sauce in sweetness is subdued. Brewed soy sauce prevails. these regions tends to have less HEMF (4-Hydroxy- Chukyo: Somewhat similar to Outlying Areas in Kanto 2(5)-ethy-5(2)-methyl-3(2H)-furanone), which is the and the Tokyo Metropolitan Area, as sweetness and umami typical aroma of brewed soy sauce. Soy sauce in are subdued and hydrolyzed vegetable protein is not used. Hokkaido is considered to have a low mixed ratio of Kinki: Sweetness and umami are subdued, and there is fermented soy sauce, as dashi soy sauce is common in no hydrolyzed vegetable protein present, but the salt the region. Soy sauce used in Outlying Areas in Kanto content varies among products. and the Tokyo Metropolitan Area, Chukyo and Kinki Shikoku: The umami is prominent, and sweetness is has a high HEMF concentration, indicating that brewed rather prominent as well, but the soy sauces contain no soy sauce is favored in these regions. (Figure 4) hydrolyzed vegetable protein. Salt content is not low. Chugoku: Sweetness is prominent, and umami is the HEMF concentration (ppm) most prominent of all regions, while the brewed aroma 60 is subdued. Hydrolyzed vegetable protein is used. 50 Kyushu: Sweetness is the most prominent of all regions 40 and the umami is prominent as well, while the salt content 30 is lower. Hydrolyzed vegetable protein is present. 20 Ⅲ. Sensory Evaluation 10 [Groupings of Soy Sauce Products from Individual 0 Regions and Sensory Characteristics of Each Group] Outlying Tokyo HokkaidoHokurikuTohoku Areas Metropolitan Chukyo Kinki ShikokuChugokuKyushu in Kanto Area As with the aforementioned component analyses, we Figure 4 Mean HEMF concentration of the five bestselling products in each region compiled samples based on data from the Nikkei POS Information Service (soy sauce category from 2011 to [Glutamic Acid Concentration,Nucleic Acid Concentration 2013, except for Hokuriku, for which the data was from (Umami)] 2012 to 2013). Five bestselling samples were selected Monosodium glutamate (MSG) and nucleic acid from each of the ten regions (Hokkaido, Tohoku, (guanosine monophosphate (GMP), and inosine Hokuriku, Outlying Areas in Kanto, Tokyo monophosphate (IMP)) work synergistically to increase Metropolitan Area, Chukyo, Kinki, Chugoku, Shikoku, umami.Many soy sauce products in Hokuriku, and Kyushu). Where the total share of the five Chugoku, Shikoku and Kyushu impart a prominent bestselling samples amounted to less than 40% umami, as they have well-balanced monosodium (Hokuriku, Chugoku and Kyushu), up to 5 samples glutamate and nucleic acid content. In contrast, fewer were added so that the total share in the region reached soy sauce products in the Tokyo Metropolitan Area, 40%. Thus, a total of 62 samples were subjected to Outlying Areas in Kanto, Chukyo and Kinki contain evaluation. Each sample was evaluated by quantifying nucleic acid. (Figure 5) the intensity of the following 13 properties on a 9-point The MSG equivalent of umami intensity = u + 1200u × v, where u is MSG -scale(scoring): alcohol smell, refreshing smell, pickled concentration (g/dl), v is IMP concentration (g/dl), and the umami intensity of GMP daikon radish smell, kombu smell, katsuobushi (dried