Quality Analysis of Non-Alcoholic Malt Drinks: Phenolic Compounds, Acids, and Nutritional Standards

Analysis, Pages 6 (1438 words)

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Result and Discussion

In the current study, total phenol, total flavonoid, ascorbic acid, free amino acid, organic acids, pH and Brix amounts in non-alcoholic malt drinks are determined.

The acceptable range of pH is 3.6–4.5 for classic malt beverage and 2.8-3.8 for flavored ones based on Iranian national standards. Additionally, the minimum amount of brix is determined 4.5 g/100 g in malt drinks. Brix of the flavored malt beverages can be varied in the range of 4.5-9 g/ 100 g. The pH mean measured was 3.

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56 ± 0.34, which ranged from 2.86 to 4.86. The pH mean for classic malt beverages was 4.15 0± 0.72, of which 14% were outside the standard range.

The pH mean for flavored malt samples was 3.33 ± 0.34, all of which was in the standard range. In general, only 4% of the samples were out of the standard range. Regarding the pH effect on flavor and susceptibility to microbial spoilage, it is notable that the pH amount must be checked before distribution in the production stage. The Brix mean was 7.69 ± 2.41( g/100g solution) which ranged from 4.

66 to 9.59. The Brix mean for classic malt beverages was 5.92 ± 0.67 and all of them were in the standard range. The mean Brix for flavored malt drinks was 8.38 ±0.92 and 4% of these samples were out of standard range. Generally, only 3% of the samples had Brix outside the standard range.

p-value analysis of Brix and pH values among different brands of malt beverages with One-Way ANOVA test showed that there was a significant difference in pH between different brands (P Descriptive statistics are shown in Table 1 for total phenol, total flavonoid, ascorbic acid, and free amino acids.

p-value significant differences were observed in the amount of total phenol, total flavonoid and amino acid in different malt beverage flavors. Further inspection showed that this difference was mainly due to differences in classical taste with other flavors. There were also significant differences in the amount of total phenol, total flavonoid and amino acid in different malt beverage brands.

According to MEBEK, the range of free amino acids in beer should be 100-120 mg/l (9. Only 1% of our samples had amounts higher than this range. The others were in or lower than that. Free amino acids appear to be a good indicator of the efficiency of the fermentation process at the production stage of barley malt extract(11). Since the fermentation process has been eliminated in the process of producing non-alcoholic malt drinks in Iran, low levels of amino acids may not be a problem(5), but given that the Brix content of most samples is acceptable and the amino acid content of most samples is lower than acceptable range, It can be concluded that fraud on malt beverages has been done to correct Brix.

MEBAK expresses that the standard total phenol range for beer is 150-200 mg/l (9). The results of our study show that only 33% of the samples are in this range. In the Moura N.N et al. study in 2016, the phenolic compounds of Brazilian beers in different types were investigated and the results were analyzed by chemometric methods.

The study showed that the amount of phenolic compounds in alcoholic beers with high bitterness was higher than that of non-alcoholic beers and beers with low bitterness(12). the study of Hosseini E et al. showed that total phenol content of oat and barley malt drinks were between 215 to 350 mg GAE /l. compared to the present study only 15% of our sample had total phenol contents higher than 215 GAE /l.(13) Polyphenols have a significant impact on the flavor and bitterness of malt products, and are also partly influential in the color of these products. Phenolic compounds slow down the oxidation process and lead to a longer shelf life of beers and the consumption of foods containing phenolic compounds has a beneficial effect on human health(14). Therefore Malt drinks should be further investigated for total phenol content.

According to the national standard of Iran Maximum of ascorbic acid content in malt beverages is 400 mg / l. In our study, 30% of the samples were higher than the maximum determined amount. Regarding the proven antioxidant effects of ascorbic acid, phenolic, and flavonoids compounds, an acceptable amount of ascorbic acid along with phenolic and flavonoids compounds can produce favorable antioxidant effects on malt beverages.

Examination of the levels of four organic acids, acceptable as an additive in national Iranian standard, in different malt beverage brands using the One-Way ANOVA test, showed a significant difference in the amount of malic and lactic acid. This difference was not observed for citric and tartaric acid. One-way ANOVA test showed significant differences between citric, malic and lactic acid among different flavors.

The analysis of the other six organic acids was performed using a One-Way ANOVA test and showed that the amount of these organic acids was significantly different in different malt beverage brands.

Regarding different flavors of malt drinks There was a significant difference between oxalic, fumaric, acetic and propionic acid, but no difference was found between succinic and gallic acid

Based on Table 3, the results tie well with similar studies wherein succinic acid has the highest level among organic acids in malt beverages. However, no tartaric acid was detected in our samples. Excluding tartaric acid, among 4 organic acids that can be used as an additive in malt beverages according to Iran national standard (tartaric acid, malic acid, lactic acid, and citric acid), the highest values were referred to citric and malic acid.

Sanarico et al. in 2003 measured the organic acids of traditional balsamic vinegar of Reggio Emilia Italy including citric, malic, tartaric, lactic, gluconic and succinic acid by HPLC method with an ion-exchange column and UV detector at 210 nm. Acid concentrations varied widely in this study and acetic acid was the major component in this group of compounds (6). A study was carried out by Tasev K et al. in 2016 on red and white wine to determine the organic acids using reverse phase chromatography. Isolation performed by an isocratic column with a C18 column (7). According to Violeta Nour et al. study in 2010, the amounts of citric, oxalic, citric, tartaric, malic, ascorbic and lactic organic acids determined by the HPLC method. In this study, 10 species of citrus fruits investigated and citric acid was the predominant acid in all of them (8).

A research was done on various juices in order to measure 9 organic acids (including oxalic, citric, malic, kinetic, galacturonic, ascorbic, succinic, and fumaric acid) by Fabio C et al. in 2005 using ion-exclusion HPLC method. In the mentioned study, 18 brands of fruit juice from 4 different types investigated and regardless of the type, the highest values observed in the fruits belong to citric and malic acid. Additionally, pear juice had the highest amount of succinic acid compared to other juices (1).

Compared to the present study, citric, malic, and succinic acid had the highest values in both studies, but naturally, the total amount of organic acids in fruit juices is much higher than the amounts of organic acid in malt beverages, Kelebek et al. evaluated the organic acids, sugars, phenolic compounds and antioxidant capacity of the orange juice and wine in the Kozan region in Turkey by the HPLC method in 2009. They studied three organic acids including citric, malic and ascorbic acid. In their study, citric acid had the highest value among rest organic acids (2). Compared to our study, ascorbic acid and malic acid had higher values in alcohol-free malt beverages, but citric acid and gallic acid values in wine were significantly higher than non-alcoholic malt drinks. In another study in 2015 Ten types of barley grains and their malts investigated by Daniel O et al. and no gallic acid found (3). Therefore, low levels of gallic acid in malt drinks are not unexpected.

According to Luigi Montanari et al.in 1999, the quantities of organic acids found in beer based on some literature are as follows: 56-230 mg / l citric acid, 14- 105 mg/l malic acid, 36-166 mg/l succinic acid, lactic acid 44- 292 mg / l acetic acid, 37-171mg / l acetic acid, 12-30 mg / l gallic acid and only presence of fumaric acid in beer was reported (4). In the case of citric, malic and succinic acid, the amount detected in our study is higher than the amount of these acids in beer, whereas the gallic acid amount is lower than the above-mentioned range. Similar values were observed for lactic, fumaric and acetic acid. Among these organic acids, only citric and partly malic are of primary origin and the rest is due to the fermentation process (4). In the present study, the fermentation process has been eliminated in the production process of non-alcoholic commercial malt beverages (5). The low amounts of citric and malic acid can be attributed to the impact of the fermentation process on beer products.