Fermentation of coffee pulp using indigenous lactic acid bacteria with simultaneous aeration to produce cascara with a high antioxidant activity

Abstract

Coffee pulp which is a by-product of coffee production contains considerable amounts of phenolic compounds that can be valorised to produce cascara as an antioxidant beverage. The fermentation and drying conditions of the coffee pulp have a great influence on the bioactive compounds in the cascara. This study aimed to investigate the effect of natural fermentation with simultaneous aeration on the phenolic content and antioxidant activity of cascara. A systematic study was carried out using a response surface methodology with a face-centered central composite design to determine the effect of fermentation time (0–8 h) and temperature (27–37 °C) on the number of bacteria in the coffee pulp after natural fermentation with simultaneous aeration (an air flowrate of 4 m/s) as well as phenolic content and antioxidant activity of cascara. The experimental dataset was modelled with an empirical model using multi-variable non-linear regression. A good agreement between model and experimental data was obtained. At the optimum conditions (4.2 h, 31.8 °C), the phenolic content was 6.72% whereas the antioxidant activity was 27.6%. Indigenous lactic acid bacteria were also isolated from the coffee pulp and determined as Leuconostoc pseudomesenteroides . The isolated bacteria can be used as a starter for controlled fermentation of coffee pulp as it increased the antioxidant activity up to 15% higher than the antioxidant activity of cascara obtained at the optimum conditions for natural fermentation with simultaneous aeration and 30% higher from the fresh coffee pulp.

Coffee by-products as the source of antioxidants: a systematic review

“…The antioxidant activity could also be improved by fermentation process using proper bacteria. 47,50 Nonetheless, extraction using more sophisticated solvent, such as supercritical CO 2 , did not contribute to higher anti-oxidant activity (IC 50 > 250 μg/mL). 48 Since coffee by-products contain nutrients and antioxidants, they might be used as food additives or animal food sources.…”

“…Other antioxidant assays included FRAP, 37,38,42,43 ABTS, 38,43,45,49,53 NO, 45,47 ORAC 42,51 and Folin-Ciocalteu. 45 Pre-treatments such as fermentation, 47,50 vacuum drying, 52 sun-drying, 37 and lipophilization 42,49 were found to yield the optimum value of antioxidant capacity. Other than crude extract, the reports also investigated the antioxidant properties of products made by coffee cascara such as dietary fiber, 53 instant beverage powder 43 lotion, 46 fodder, 37 anthocyanin, 44 and essential oil.…”

Evaluation of antioxidant, organic acid, and volatile compounds in coffee pulp wine fermented with native yeasts isolated from coffee cherries

“…In addition, coffee pulp contains cellulose (13–27%), lipids (2–17%), proteins (9–11%), tannins (4.5%), pectin substances (6.5%), reducing sugars (12.4%), and nitrogen extracts (57–63%) (Pleissner et al, 2016). Coffee pulp is additionally used for the production of bio-products such as compost and vermicompost (Murthy and Naidu, 2012), animal feed (Murthy and Naidu, 2012; Oktaviani et al, 2020), bioenergy (Bonilla-Hermosa et al, 2014), sugar (Murthy and Naidu, 2012), flour (Velez and Lopez, 2017), aroma compounds (Bonilla-Hermosa et al, 2014), and cascara (Heeger et al, 2017). Cascara, also known as coffee cherry tea, is an infusion of dried coffee cherry pulp.…”

Lactobacillus Use for Plant Fermentation: New Ways for Plant-Based Product Valorization

“…More recently, coffee cherry pulp has been used in infusion to obtain an AO drink called cascara. To improve the AO activity of this beverage, it was fermented by endophytic L. casei [92]. A turmericbased functional drink was also obtained by co-fermentation with Enterococcus faecium, Lactococcus lactis subsp.…”