Study of Brewer's Spent Grain Environmentally Friendly Processing Ways

BACKGROUND

This article is devoted to the study of the effect of electrochemically activated water (catholyte with pH 9.3) on organic compounds of the plant matrix of brewer's spent grain in order to extract various compounds from it.

METHODS

Brewer's spent grain was obtained from barley malt at a pilot plant by mashing the malt followed by filtration and washing of the grain in water and storing it at (0 ± 2) °C in craft bags. For the organic compound quantitative determination, instrumental methods of analysis (HPLC) were used, and the results were subjected to mathematical analysis.

RESULTS

The study results showed that at atmospheric pressure, the alkaline properties of the catholyte showed better results compared to aqueous extraction with respect to β-glucan, sugars, nitrogenous and phenolic compounds, and 120 min was the best period for extraction at 50 °C. The excess pressure conditions used (0.5 ÷ 1 atm) revealed an increase in the accumulation of non-starch polysaccharide and nitrogenous compounds, while the level of sugars, furan and phenolic compounds decreased with increasing treatment duration. The waste grain extract ultrasonic treatment used revealed the effectiveness of catholyte in relation to the extraction of β-glucan and nitrogenous fractions; however, sugars and phenolic compounds did not significantly accumulate. The correlation method made it possible to reveal the regularities in the formation of furan compounds under the conditions of extraction with the catholyte: Syringic acid had the greatest effect on the formation of 5-OH-methylfurfural at atmospheric pressure and 50 °C and vanillic acid under conditions of excess pressure. Regarding furfural and 5-methylfurfural, amino acids had a direct effect at excess pressure. It was shown that the content of all furan compounds depends on amino acids with thiol groups and gallic acid; the formation of 5-hydroxymethylfurfural and 5-methylfurfural is influenced by gallic and vanillic acids; the release of furfural and 5-methylfurfural is determined by amino acids and gallic acid; excess pressure conditions promote the formation of furan compounds under the action of gallic and lilac acids.

CONCLUSIONS

This study showed that a catholyte allows for efficient extraction of carbohydrate, nitrogenous and monophenolic compounds under pressure conditions, while flavonoids require a reduction in extraction time under pressure conditions.

Physico-chemical study of steroids from different matureness corn silk material

This study shows an ultrasonic assisted extraction procedure of steroids from corn silk (CS). The total steroids contents were positively correlated with the ultrasonic assisted extraction time. The extracted steroids contents varied according to the different maturity stages of CS. There were three tested CS maturity stages: silking stage (CS-S), milky stage (CS-M) and mature stage (CS-MS). The β - sitosterol standardization method with 530 nm wavelength colorimetric measurements were applied to determine the content of extracted steroids. Measured steroids concentrations range were from 38.3 × 10-3 mg.mL-1 to 368.9 × 10-3 mg.mL-1 in different extraction time and CS maturity stages. The highest concentration of steroids, 368.9 × 10-3 mg.mL-1 was found in CS-MS sample with the 75 minutes ultrasonic extraction time. The fluorescence mapping techniques were used to confirm the existence of steroids. The thermal analysis illustrated a typical multistep decomposition process for the CS-S, CS-M and CS-MS samples. Two endothermic peaks were found: The first one was 54.3 °C for CS-S and CS-MS, 60.2 °C for CS-M, the second one, 397 °C (CS-MS), 415.1 °C (CS-M) and 419.7 °C (CS-S) attributed to the total thermal decomposition. The observed exotheric process found at 524 °C corresponded to CS-MS sample decomposition. The optimal ultrasonic-assisted extraction time for all samples under study CS-S, CS-M and CS-MS was about 75 minutes and the optimal steroids extraction contents obtained were 92.8 × 10-3 mg.mL-1 (CS-S), 124.2 × 10-3 mg.mL-1 (CS-M) and 368.9 × 10-3 mg.mL-1 (CS-MS) respectively.

Physico-chemical study of flavonoids from different matureness corn silk material

There was tested a simple extraction procedure of flavonoids separation from the original corn silk (CS) material. It was found, that the total flavonoids content differs with the extraction time and extraction temperature. There were found different flavonoids contents in extracts prepared from different maturity stages of the original corn silk material (silking stage (CS-S), milky stage (CS-M)). Extracted flavonoids content was quantified by the lutin standardization method by means of colorimetry at 510 nm wavelength. Obsreved flavonoids concentration was ranging from 2×10-3 mg.mL-1 to 7 ×10-3 mg.mL-1 dependent on the extraction time period and extraction temperature. The highest flavonoids concentration of 7.5×10-3 mg.mL-1 was found for CS-M after 20 minutes extraction time and 80  °C extraction temperature. There was confirmed the presence of flavonoids by fluorescence mapping experiments. There was found a typical multistep decomposition process for both CS-S and CS-M materials by TG analysis. There was found a melting temperature of flavonoids of 54.3 °C for corn silk silking stage material exhibiting 58.9 J.g-1 heat of fusion and 60.2 °C for corn silk milky stage material with 112.9 J.g-1 heat of fusion. The optimal conditions of corn silk flavonoids extraction were 40 ℃, 50 minutes for CS-S, the optimal flavonoids extraction content was (6.8 ±2.1)×10-3 mg.mL-1, 80℃, 20 minutes for CS-M and the optimal extraction content was (7.2 ±0.3)×10-3 mg.mL-1.

Addition of rutin/quercetin mixture to spreadable processed cheese: antioxidant and textural characteristics

Spreadable processed cheese is a traditional product made from a mixture of cheese, fat, water and emulsifying salts.The aim of this research was prepared spreadable processed cheese with new functional properties. Spreadable processed cheese enriched with the mixture (1:1) of rutin and quercetin (1.0 g.100g-1) was prepared at two melting temperature (80°C and 90°C) for three holding times (1, 5 and 10 min). The effect of melting temperature and holding time on the quercetin and rutin content was assessed using liquid chromatography with UV detection after ultrasonic-assissted extraction to methanol. The corresponding antioxidant characteristics were determined using spectrophotometric assays for total phenolics (TPC) and radical scavenging activities DPPH and ABTS. The extraction yield for quercetin varied from 45.8 to 66.4% and from 12.8 to 40.8% for rutin. The level of quercetin significantly descrased with the increase of holding time, while rutin content has increased with the increase of melting temperature. TPC values ranged from 10.8. to 14.8 mg GAE·g-1 in SPC sample enriched with rutin/quercetin mixture, and the increase of melting temperature resulted in the decrease of TPC values. DPPH and ABTS assays did not reveal any statistically significant pattern using Kruskal-Wallis ANOVA. The addition of the mixture of flavonoids into the processed cheese significantly reduced the complex modulus in comparison with the control sample (without flavonoids). This indicate that the structure of enriched SPC sample was more flexible than those in control processed cheese samples. Both melting temperature and holding time increased the complex modulus. Spreadable processed cheese are scarcely used as a carrier of flavonoids in scientific researches probably due to very complex matrices. Our research proved that spreadable processed cheese containing rutin/quercetin mixture can be used as a functional food.