Enzymes Extracted from Apple Peels Have Activity in Reducing Higher Alcohols in Chinese Liquors

Abstract

As the unavoidable byproducts of alcoholic fermentation, higher alcohols are unhealthy compounds widespread in alcoholic drinks. To investigate the activity of apple crude enzymes toward higher alcohols in liquors, five kinds of apple peels, namely, Fuji, Gala, Golden Delicious, Red Star, and Jonagold, were chosen to prepare enzymes, and three kinds of Chinese liquors, namely, Xifeng (containing 45% ethanol), Taibai (containing 50% ethanol), and Erguotou (containing 56% ethanol), were tested. Enzymes were prepared in the forms of liquid solution, powder, and immobilized enzymes using sodium alginate (SA) and chitosan. The treatment was carried out at 37 °C for 1 h. The relative amounts of different alcohols (including ethanol, 1-propanol, isobutanol, 1-butanol, isoamylol, and 1-hexanol) were measured using gas chromatography (GC). Conditions for preparing SA-immobilized Fuji enzymes (SA-IEP) were optimized, and the obtained SA-IEP (containing 0.3 g of enzyme) was continuously used to treat Xifeng liquor eight times, 20 mL per time. Significant degradation rates (DRs) of higher alcohols were observed at different degrees, and it also showed enzyme specificity according to the apple varieties and enzyme preparations. After five repeated treatments, the DRs of the optimized Fuji SA-IEP remained 70% for 1-hexanol and >15% for other higher alcohols.

Chemical Composition and Safety of Unrecorded Grain Alcohol (Bai Jiu) Samples from Three Provinces in China

“…Higher alcohols are natural byproducts of fermentation; they are important to flavor and are not noted as significant health risks. Some studies have discussed higher alcohol being a potential health hazard in excessive amounts, and its effect is similar to that of ethanol [23,24,25,26]. However, Lachenmeier and Rehm in their editorial [26], stated that there is no evidence for the impact of higher alcohols in unrecorded alcohol on public health.…”

Basic flavor types and component characteristics of Chinese traditional liquors: A review

“…Therefore, they can carry nonvolatile and low-boiling molecules within other components through the volatilization process, consequently enhancing aroma. The total alcohol content controls the body flavor (Han, Shi, Zhu, Lv, & Du, 2014) and must be moderate, as a lower content yields thin, bitter liquor. Specifically, isoamyl alcohol, n-butanol, isobutanol, and n-propanol are irritating and bitter, whereas glycerol and 2,3-butanediol exhibit no bitter irritation.Rather,they are thick and slightly sweet,which can improve liquor sweetness, softness, and naturalness.…”

“… Note : “—” indicates no report. The included data were collectively derived from the references (Han et al., 2014; Liu & Sun, 2018; Lu, et al. 2019; Jin et al., 2017; Ma et al., 2012; Qian & Xue, 1997; Wang, 2011; Zhang, 2019).…”

Three main flavour types of Chinese Baijiu: characteristics, research, and perspectives

“…Moutai Baijiu contains 56 different alcohols, at a concentration of about 1.6 g/L, which accounts for 15% of the total aroma compounds ( 19 ) . In Moutai Baijiu, the amount of higher alcohol and alcohols with high boiling points are greater than in Baijius of other flavours.…”

“…In Moutai Baijiu, the amount of higher alcohol and alcohols with high boiling points are greater than in Baijius of other flavours. Among them, the content of isoamyl alcohol, n‐propanol, isobutanol, heptanol, and octanol are the highest, with isoamyl alcohol at approximately 0.5 g/L ( 5, 19 ) . Heptanol and octanol, absent in other Baijiu flavours, are present in Moutai‐flavour Baijiu, ranging from 0.06 to 0.1 g/L.…”