ABSTRACT Microbial contamination of the wort during the fermentation process causes significant losses in ethanol production worldwide and creates a dependence of the industry on chemicals and antibiotics to control contamination. Therefore, this study used electron beam (e-beam) to disinfect wort from sugarcane (Saccharum officinarum L.) molasses and investigate the bioethanol fermentation. Four treatments (T0 – T3) were carried out using ionizing doses of radiation through the electron accelerator: 0 (control), 10, 20, and 40 kGy. Total mesophiles, total bacteria, sucrose, glucose, fructose, phenolics, flavonoids, hydroxymethylfurfural (5-HMF), and Furfural were measured. An alcoholic fermentation assay was performed after the irradiation process. The irradiated treatments showed no inversion of sugars and formation of the inhibitory by-products flavonoids, furfural and 5-HMF, except for the phenolic compounds. The lower dose tested (10 kGy) reduced more than 99.9 % of the total mesophiles and more than 99.99 % of the total bacteria in the substrate. In the fermentation, the irradiated worts presented similar (p > 0.05) yields (92, 93, and 94 %) and ethanol productivity levels (0.89, 0.88, and 0.87 g L–1 h–1, for T1, T2, and T3 respectively). However, all treatments presented higher yields and productivity (p < 0.05) when compared to the control (88 % and 0.85 g L–1 h–1), highlighting the possible use of e-beam in wort fermentation at a lower dose (10 kGy). This allows reduction in losses caused by microbial contamination, besides increasing fermentation yield and productivity with lower energy consumption.

Penicillium expansum é o agente causador da doença em maçã conhecida como mofo azul. O efeito inibitório da capsaicina derivada dos frutos Capsicum spp. e da levedura Hansenula wingei foi avaliado através de ensaios in vitro e in vivo em maçã. A concentração inibitória mínima da capsaicina de 122,16 µg mL-1 foi determinada usando microdiluição. A capsaicina não mostrou capacidade em reduzir a incidência do mofo azul na maçã. Entretanto, um retardo no crescimento do fungo foi observado nos 14 primeiros dias dos ensaios in vivo. Também descrevemos o efeito da levedura Hansenula wingei AM2(-2) isolada e em combinação com tiabendazol em baixa dosagem (40 µg mL-1) no controle da doença de maçãs por P. expansum.Hansenula wingei AM2(-2), em combinação com baixa dosagem de tiabendazol (10% da recomendada pelo fabricante), apresentou 100% de eficácia após 7 dias de estocagem a 21 ºC, seguido de 80,45% e 72,13% de eficácia após 14 e 21 dias, respectivamente(p > 0,05). Estes resultados contribuem com as novas opções de emprego de agentes antifúngicos contra Penicillium expansum.

Penicillium expansum is the causative agent of apple blue mold. The inhibitory effects of the capsaicin derived from Capsicum spp. fruits and yeast Hansenula wingei against P. expansum were evaluated in an in vitro and in in vivo assay using Fuji apples. The minimum inhibitory concentration of capsaicin determined using the broth micro-dilution method was 122.16 µg mL-1. Capsaicin did not reduce blue mold incidence in apples. However, it was able to delay fungal growth in the first 14 days of the in vivo assay. The in vivo effect of the yeast Hansenula wingei AM2(-2), alone and combined with thiabendazole at low dosage (40 µg mL-1), on the incidence of apple diseases caused by P. expansum was also described. H. wingei AM2(-2) combined with a low fungicide dosage (10% of the dosage recommended by the manufacturer) showed the best efficacy (100%) up to 7 days of storage at 21 ºC, later showing a non-statistically different decrease (p > 0.05) after 14 (80.45%) and 21 days (72.13%), respectively. These results contribute providing new options for using antifungal agents against Penicillium expansum.