A Central Composite Design in increasing the quercetin content in the aqueous onion waste isolates with antifungal and antioxidant properties

In this study, to increase the content of quercetin in the isolates obtained from the white and red onion scales, in accordance with the zero waste philosophy, using water as an environmentally and healthy friendly extractant, a mathematical model was constructed, based on the Central Composite Design. The suitability of the model for the accurate and quick study of complex relationships was demonstrated by obtaining a statistically insignificant difference in the yield predicted by the model and that determined experimentally under optimal extraction conditions, i.e., 44.14 mg/g (33.57 mg/g) and 45.54 mg/g (33.31 mg/g) for white (red) onion scales, respectively. To present the obtained isolates applicability, their biological activity was assessed in terms of antioxidant activity and antifungal activity against various fungi, showing properties that are sufficient to encourage the use of this material, previously treated as worthless waste, for the production of various functional ingredients, including functional food additives. Moreover, they can be also used to produce safe and effective protectants meeting the GRAS criteria.

Biological control of soil-borne phytopathogenic fungi through onion waste composting: implications for circular economy perspective

The production of onion waste derived mainly from bulbs affected by fungal diseases, during onion classification and storage presents an important agro-environmental issue in onion production regions. Composting is an environmentally friendly strategy to recycle agricultural waste and produce organic fertilizers. Modifications of the microbial community in soil can affect the ability of pathogen propagules to survive, germinate and infect plant roots. Hence, the main objective of this work was to exploring the mechanisms involved on the presence of three soil-borne phytopathogenic fungi during the composting process of onion waste under the hypothesis if that the resulting compost effectively prevents or minimizes the dispersion of phytopathogenic fungi. To this end, three composting piles of 60 tonnes each were built by layering onion waste affected by phytopathogenic fungi and cow dung at 1:1 ratio. Temperature, moisture, pH, electrical conductivity (EC) and Aspergillus niger, Penicillium sp. and Fusarium sp. growth were monitored for 100 days. During the first 28 days of composting, the presence of phytopathogenic fungi increased significantly showing thereafter a downward trend. Final estimations of fungal populations densities indicated a predominance of A. niger and an effective reduction in the abundance of Fusarium sp. This pilot-scale work demonstrates the feasibility of composting onion waste contaminated with phytopathogenic fungi and highlights the positive environmental impact associated with this practice. Therefore, the composting of onion waste and cow dung is a feasible and sustainable procedure to recycle onion waste and to promote circular economy in onion production regions.

MEWUJUDKAN DESA INOVASI TEKNOLOGI MELALUI PENGGUNAAN KOMPOSIT (RESIN DAN SERBUK LIMBAH BAWANG) DI DESA BANGSRI DAN DESA PESANTUNAN KABUPATEN BREBES

TThe area of harvested shallots in Brebes is 60.82% of the total harvested area in Central Java Province. Production of shallots in 2018 reached 10,519,484 quintals. Pesantunan Village, Wanasari District, has a high productivity of 121.544 quintals/Ha and Bangsri Village has a productivity of 98.28 quintals/Ha. The abundant potential of onions also has an impact on the abundant onion waste, so that the potential for this onion waste will be made a composite as the embodiment of the Innovation Village. The purpose of this community service activity is to create a Technology Innovation Village to community groups in Pesantunan and Bangsri Villages regarding the use of onion waste into a composite.The method offered is divided into two, namely Soft Program and Hard Program.The result of the composite technology innovation village program, number of participants in the Pesantunan Village was 25 from the "Santun Asri" community group and 15 people in the Bangsri Village from the "Bumdes" membership. Participants were provided with a soft program including waste management and technology innovation villages in the composite field. Participants were also provided with a Hard Program, is practicing making composites with waste onions

Rapid Assessment of Anthocyanins Content of Onion Waste through Visible-Near-Short-Wave and Mid-Infrared Spectroscopy Combined with Machine Learning Techniques

A sustainable process for valorization of onion waste would need to entail preliminary sorting out of exhausted or suboptimal material as part of decision-making. In the present study, an approach for monitoring red onion skin (OS) phenolic composition was investigated through Visible Near-Short-Wave infrared (VNIR-SWIR) (350–2500 nm) and Fourier-Transform-Mid-Infrared (FT-MIR) (4000–600 cm−1) spectral analyses and Machine-Learning (ML) methods. Our stepwise approach consisted of: (i) chemical analyses to obtain reference values for Total Phenolic Content (TPC) and Total Monomeric Anthocyanin Content (TAC); (ii) spectroscopic analysis and creation of OS spectral libraries; (iii) generation of calibration and validation datasets; (iv) spectral exploratory analysis and regression modeling via several ML algorithms; and (v) model performance evaluation. Among all, the k-nearest neighbors model from 1st derivative VNIR-SWIR spectra at 350–2500 nm resulted promising for the prediction of TAC (R2 = 0.82, RMSE = 0.52 and RPIQ = 3.56). The 2nd derivative FT-MIR spectral fingerprint among 600–900 and 1500–1600 cm−1 proved more informative about the inherent phenolic composition of OS. Overall, the diagnostic value and predictive accuracy of our spectral data support the perspective of employing non-destructive spectroscopic tools in real-time quality control of onion waste.

Bioanodes Containing Catalysts from Onion Waste and Bacillus subtilis for Energy Generation from Pharmaceutical Wastewater in a Microbial Fuel Cell

We propose the integration of bioanodes composed of onion waste (OW)-derived catalysts + Bacillus subtilis (B. subtilis) for application in a Microbial Fuel Cell (MFC). OW is activated by pyrolysis...