Effect of Nuruks and Crude Amylolytic Enzyme on Free Amino Acid and Volatile Components of Brown Rice Vinegar Prepared by Static Culture

Abstract

The effect of nuruks and crude amylolytic enzyme on free amino acid and volatile components of brown rice vinegar prepared by static cultures was investigated. Five groups consisted of AV (100% nuruk without crude amylolytic enzyme), BV (75% nuruk; 25% crude amylolytic enzyme), CV (50% nuruk; 50% crude amylolytic enzyme), DV (25% nuruk; 75% crude amylolytic enzyme) and EV (100% crude amylolytic enzyme without nuruk). Free amino acid content in AV vinegar (132.06 mg%) was lower than the others (184.56-191.22 mg%). Acetic acid, 3-methyl butyl acetate, acetoin and isoamyl alcohol were major volatile components as analyzed using gas chromatography-mass spectrometry after headspace solid-phase microextraction. Acetic acid in AV and EV samples represented 67.56% and 55.53% of total GC peak area, respectively. E-nose provided different patterns in each case showing variation in sensory properties.

Enhanced antioxidant capacity of brown rice vinegar supplemented with soy residue

“…Among the acids, acetic acid had the highest proportions, at 24.48% in BRV, 35.70% in BROV3, and 24.6% in BROV5. Acids are oxidation products produced by acetic acid bacteria (Lee et al, 2011). As the main volatile compounds of vinegar, acids have a pungent odor, which affects the sensual flavor of vinegar (Kim et al, 2011).…”

“…Acetoin is produced during alcoholic fermentation (Kim et al, 2020). It has a sweet, buttery, and creamy odor (Lee et al, 2011) but causes bad odors in brews and juice drinks (Jo et al, 2016). Acetoin content was highest in BROV5 (6.38%), followed by BROV3 (3.43%) and BRV (1.02%).…”

“…Isoamyl acetate is an ester found in the aromatic component of vinegar and generates the aroma of pears, bananas, and apples (Yoon et al, 2010). Phenethyl acetate is produced when phenylethyl alcohol is esterified with acetic acid and is a good fragrance component that produces various flavors, such as honey, rose, and apple (Lee et al, 2011). BRV had twice higher concentrations of isoamyl acetate and phenethyl acetate than the BROVs.…”

Solid Fungi Starters Using Aspergillus spp. under Different Manufacturing Conditions

“…The total free amino acid content appeared in the order BS1 10,563.2 μg/mL > DH1 10,491.7 μg/mL > EH5 10,406.9 μg/mL > AS1 9722.7 μg/mL > CH1 8713.3 μg/mL (Figure 2). Therefore, the use of an inoculum containing amino acids that affect taste should contribute to the production of various fermentation products [29,30].…”

Identification of the Predominant Species of Bacillus, Staphylococcus, and Lactic Acid Bacteria in Nuruk, a Korean Starter Culture

“…Bacillus subtilis을 종균으로 개발하여 첨가하고 있다 [7,8]. 한편, 술이나 식초와 같이 발효제가 필요한 경우에는 자연발 효로 만들어진 재래식 누룩과 Aspergillus kawachii, Aspergillus oryzae를 접종하여 만드는 개량누룩, 멸균한 전 분질 원료에 곰팡이를 배양한 코지(koji), 그리고 효소제 등 이 사용되고 있다 [23,24]…”