Comparison of Key Aroma Compounds in Five Different Types of Japanese Soy Sauces by Aroma Extract Dilution Analysis (AEDA)

Abstract

An investigation by the aroma extract dilution analysis (AEDA) technique of the aroma concentrate from five different types of Japanese soy sauces, categorized according to Japan Agricultural Standards as Koikuchi Shoyu (KS), Usukuchi Shoyu (US), Tamari Shoyu (TS), Sai-Shikomi Shoyu (SSS), and Shiro Shoyu (SS), revealed 25 key aroma compounds. Among them, 3-ethyl-1,2-cyclopentanedione and 2'-aminoacetophenone were identified in the soy sauces for the first time. Whereas 3-(methylthio)propanal (methional) and 3-hydroxy-4,5-dimethyl-2(5H)-furanone (sotolon) were detected in all of the soy sauce aroma concentrates as having high flavor dilution (FD) factors, 4-ethyl-2-methoxyphenol was detected as having a high FD factor in only four of the soy sauces (KS, US, TS, and SSS). Furthermore, 5(or 2)-ethyl-4-hydroxy-2(or 5)-methyl-3(2H)-furanone (4-HEMF) and 4-hydroxy-2,5-dimethyl-3(2H)-furanone (4-HDMF), which were thought to be the key odorants in KS, were detected in KS, US, TS, and SSS, but the FD factors widely varied among them. The sensory evaluations demonstrated that the aroma descriptions of a cooked potato-like note and a caramel-like/seasoning-like note were evaluated as high scores with no significant differences among the five soy sauces. On the other hand, a burnt/spicy note was evaluated as having high scores in KS, TS, and SSS, but it was evaluated as having a low score in SS. The comparative AEDA experiments and the auxiliary sensory experiments demonstrated that the five different types of Japanese soy sauces varied in their key aroma compounds and aroma characteristics, and the key aroma compounds in KS might not always be highly contributing in the other types of Japanese soy sauces.

Analysis of volatile flavor compounds influencing Chinese-type soy sauces using GC–MS combined with HS-SPME and discrimination with electronic nose

“…Among these compounds, dozens of components were shared commonly with different amount in soy sauce products. According to the previous report (Nunomura et al 1984;Kaneko et al 2012Kaneko et al , 2013Feng et al 2015), some typical or key volatile flavor compounds, which might be the contributors to the flavor of soy sauce, were summarized in Table 2.…”

“…The amount of phenylethyl alcohol in pure soy sauce sample, sample 11 and sample 12 was similar. 1-Octen-3-ol, which is also known as mushroom alcohol, is a contributor to the flavor of Japanese-type soy sauce (Kaneko et al 2012(Kaneko et al , 2013. The concentration of this compound in pure soy sauce sample was very low.…”

“…Benzeneacetic acid ethyl ester, a high boiling point ester, did not present in aHVP sample. This compound, being one of the major contributors to soy sauce flavor (Kaneko et al 2012(Kaneko et al , 2013, was found at low concentration in pure soy sauce sample and several soy sauce products. It is noteworthy that the amount of fatty acid ester in soy sauce depends on varieties of soybean which were used in the brewing material.…”

“…Aliphatic aldehyde, 3-(methylthio)-propanal, which contain sulfur and possess a strong onion and roast meat-like flavor, was also identified in pure soy sauce, aHVP, and three soy sauce products. It was the key aroma compound and major contributor of fragrance in soy sauces (Kaneko et al 2012(Kaneko et al , 2013. Like benzeneacetaldehyde, 3-(methylthio)-propanal was also found to be positively related to 'musty' and 'soy saucelike' odors and exhibited the greatest aroma intensities (Feng et al 2013a(Feng et al , b, 2015.…”

“…Volatile chemical compounds make a critical contribution to the typical flavor of soy sauce. Volatile organic compounds in various soy sauces, including Japanese-type soy sauces (Nunomura et al 1984;Kaneko et al 2012Kaneko et al , 2013Meng et al 2012;Hayase et al 2013;Aishima 2006;Feng et al 2013a, b), Thai-type soy sauce (Wanakhachornkrai and Lertsiri 2003;Lertsiri et al 2010), Korea-type soy sauces (Baek and Kim 2004;Lee et al 2006) and Chinese-type soy sauces (Zhang and Tao 2009;Gao et al 2010;Sun et al 2010;Feng et al 2015), have been investigated and some of the volatiles such as alcohols, esters, phenols, acids, and heterocyclics have been identified.…”