Identifying yeast isolated from spoiled peach puree and assessment of its batch culture for invertase production

• Main Authors: Marcela Vega FERREIRA, Tariani Lemos de AVILA, Claudio Rafael KUHN, Ricardo Peraça TORALLES, César Valmor ROMBALDI
• Format: Article
• Language: English
• Published: Sociedade Brasileira de Ciência e Tecnologia de Alimentos
• Series: Food Science and Technology
• Subjects: spoiled peach puree; invertase; Saccharomyces cerevisiae; autolysis
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0101-20612016005031103&lng=en&tlng=en

Abstract The identification of yeasts isolated from spoiled Jubileu peach puree using the API 20C AUX method and a commercial yeast as witness were studied. Subsequently, the yeast’s growth potential using two batch culture treatments were performed to evaluate number of colonies (N), reducing sugar concentration (RS), free-invertase (FI), and culture-invertase activity (CI). Stock cultures were maintained on potato dextrose agar (PDA) slants at 4 °C and pH 5 for later use for batch-culture (150 rpm) at 30°C for 24 h, then they were stored at 4 °C for subsequent invertase extraction. The FI extract was obtained using NaHCO3 as autolysis agent, and CI activity was determined on the supernatant after batch-cultured centrifugation. The activity was followed by an increase in absorbance at 490 nm using the acid 3,5-DNS method with glucose standard. Of the four yeasts identified, Saccharomyces cerevisiae was chosen for legal reasons. It showed logarithmic growth up to 18 h of fermentation with positive correlation CI activity and inverse with RS. FI showed greater activity by the end of the log phase and an inverse correlation with CI activity. Finally, it was concluded that treatment “A” is more effective than “B” to produce invertase (EC 3.2.1.26).