Quality Characteristics and Quantification of Acetaldehyde and Methanol in Apple Wine Fermentation by Various Pre-Treatments of Mash

Effect of bentonite and calcium chloride on apple wine

BACKGROUND

Apple wine is a popular alcoholic beverage for its nutrition and fresh taste. However, the methanol existing in apple wine restricts its quality. Unfortunately, there are no methods to reduce the methanol content in fruit wine. To this end, bentonite (B), calcium chloride (CC) and their combination (B&CC) were added into apple juice in this study. The treated juice (0) and supernatant obtained by standing the juice at 25 °C for 24 h were fermented at 25 °C and 10 °C, respectively.

RESULTS

Bentonite was an excellent methanol interrupter, a pectin retainer and a wine quality defender both at 25 and 10 °C. The lowest methanol content of 1.41 mg L^-1 and higher pectin content of 84.74 mg L^-1 were reached in the finished wine by B0 at 10 °C. Calcium chloride decreased pectin content, elevated methanol content and changed the profile of individual organic acids. In fact, the wine by B&CC0 at 25 °C showed dramatic changes in individual organic acids. The content of l-malic acid and succinic acid was only 2.22% and 6.29% of the control, respectively, while the lactic acid content was 17.72 times that of the control.

CONCLUSIONS

It is suggested that B0 and fermented at 10 °C was the most effective way to decrease methanol content, retain pectin content and defend wine quality. © 2021 Society of Chemical Industry.

Formulation of Novel Liqueurs from Juice Industry Waste: Consumer Acceptance, Phenolic Profile and Preliminary Monitoring of Antioxidant Activity and Colour Changes During Storage

RESEARCH BACKGROUND

Apple juice is one of the most popular and liked beverages worldwide. Due to the increased health consciousness among consumers, beetroot and chokeberry juices have also rising consumption trends. Despite representing a considerable percentage of the processed fruit and rich source of bioactive compounds, fruit pomace, remaining after juice production, has still been underutilised. Here, the possibility of using apple, beetroot and chokeberry pomace in liqueur formulations is investigated.

EXPERIMENTAL APPROACH

Apple and chokeberry liqueurs were produced from apple and chokeberry pomace extracts, respectively. Apple/chokeberry and apple/beetroot liqueurs were obtained by combining apple pomace with chokeberry and beetroot pomace extracts in ratios 50:50 and 70:30, respectively. The sensory quality and acceptability of freshly prepared liqueurs were evaluated by experts and consumers. Sugars and phenolics were identified and quantified by high-performance anion-exchange chromatography with pulsed-amperometric detection (HPAEC-PAD) and high-performance liquid chromatography-diode array detection-tandem mass spectrometry (HPLC-DAD-MS/MS), respectively. Storability was preliminarily evaluated based on monitoring of total phenolic concentration, antioxidant activity and colour each month during 6 months of storage at 4 and 22 °C.

RESULTS AND CONCLUSIONS

The expert and the consumer testing indicated that apple and chokeberry pomace could be used as raw materials without any flavour corrections while apple/beetroot pomace liqueur would require modification. High total phenolic content and antioxidant activity were found in all freshly prepared liqueurs, with chokeberry liqueur being by far superior. Among identified phenolics, ellagic acid and phlorizin were quantified as the most prominent, except in chokeberry liqueur, where phlorizin was not quantified. Despite the decrease in total phenolic concentration and antioxidant activity after 6 months, liqueurs still represented a rich source of phytochemicals. The highest phenolic compound retention and antioxidant activity maintenance were observed in chokeberry liqueur. Also, the appealing colour was retained despite the changes detected in chromatic characteristics.

NOVELTY AND SCIENTIFIC CONTRIBUTION

The possibility of apple, beetroot and chokeberry pomace restoration into the food chain by the production of liqueurs has been demonstrated for the first time. Functional and sensorial properties of newly developed liqueurs indicated that the selected pomace represents the promising raw material for liqueur production. The applied approach represents a contribution to the circular economy in juice production.