The role of chemical amendments on modulating ammonia loss and quality parameters of co-composts from waste cocoa pods

Abstract

Purpose Nitrogen loss as ammonia (NH 3) in a waste cocoa pod co-composting process was determined following the addition of three potential chemical amendments that could lower NH 3 loss. Further, amended compost products were assessed for quality and possible phytotoxicity in a pot experiment. Methods Pod borer damaged cocoa pods were co-composted in lab-scale vessels under ambient conditions with double superphosphate, phosphoric acid, and gypsum at 2%, 5% and 1% of fresh weight, respectively. NH 3 emitted during composting was trapped in standard H 2 SO 4 and determined titrimetrically. Composting mixtures were sampled on days 0, 7, 56 and 90 to monitor pH, total C, total N, and C:N ratio. Mature co-composts were incorporated to the soil at 20 t ha −1 and growth response of Chinese cabbage plants (Brassica rapa chinensis) assessed for the phytotoxicity. Results The chemical amendments were ineffective (p > 0.05) in preventing loss of NH 3 but the quality of composting mixtures were significantly (p < 0.0001) improved. The manure compost generated had acceptable parameters (C, 31.2-31.9% and C:N ratio, 9-10:1) and were free from phytotoxicity for soil application as revealed by the response of Chinese cabbage crop. Conclusions Chemical amendments used in the co-composting process mainly modulated pH without any detrimental effects on quality. The results also demonstrated that the NH 3 loss is insignificant from the cocoa waste-composting process. Further studies are required with increased rates of acidifying amendments like phosphoric acid to further augment the quality of cocoa pod composts.

Sensory evaluation of chocolate bar production materials of dry cocoa seeds in various fermentation treatments

“…During fermentation, there is a process of forming tastes, colours and aromas through the enzymic process, starting with the forma-https://doi.org/10.17221/272/2020-CJFS tion of organic acids which induce the enzymic process as well as biochemical processes resulting in colour changes and in a decrease in polyphenol compounds (Anyimah-Ackah et al 2019;Apriyanto and Umanailo 2019;Djaafar et al 2019), while changes in total fermented cocoa beans are a decrease in dry weight, an increase in peptide-N content, total reducing sugars and a decrease in sucrose and total sugar. Ganeswari et al (2015), Fidelis and Rajashekhar Rao (2017), Barišić et al (2019), and Vitinaqailevu and Rajashekhar Rao (2019) found that the concentration of free amino acids (acidic) decreases in line with the increase in the total amino acid content, hydrophobic free amino acids. After 7 days of fermentation, the theobromine content in the seeds (cotyledons) decreased and it increased in the skin (testa), due to the migration of theobromine from cotyledons to the testa during fermentation.…”