Barberis Carla L, Landa María F, Barberis Mauricio G, Giaj-Merlera Guillermo, Dalcero Ana M, Magnoli Carina E
Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta Nacional N° 36 Km 601 (5800), Río Cuarto, Córdoba, Argentina; Member of the Research Career of CONICET (CIC-CONICET), Argentina.
Departamento de Microbiología e Inmunología, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Ruta Nacional N° 36 Km 601 (5800), Río Cuarto, Córdoba, Argentina; Fellowship of the CONICET, Argentina.
Rev Iberoam Micol. 2014 Apr-Jun;31(2):131-6. doi: 10.1016/j.riam.2013.02.005. Epub 2013 Apr 11.
In the last years, food grade antioxidants are used safely as an alternative to traditional fungicides to control fungal growth in several food and agricultural products.
In this work, the effect of butylated hydroxyanisole (BHA) and propyl paraben (PP) on two hydrolytic enzyme activity (β-d-glucosidase and α-d-galactosidase) by Aspergillus section Nigri species under different water activity conditions (aW; 0.98, 0.95 and 0.93) and incubation time intervals (24, 48, 72 and 96h) was evaluated on peanut-based medium.
The activity of two glycosidases, β-d-glucosidase and α-d-galactosidase, was assayed using as substrates 4-nitrophenyl-β-d-glucopyranosido and 4-nitrophenyl-α-d-galactopyranosido, respectively. The enzyme activity was determined by the increase in optical density at 405nm caused by the liberation of p-nitrophenol by enzymatic hydrolysis of the substrate. Enzyme activity was expressed as micromoles of p-nitrophenol released per minute.
The major inhibition in β-d-glucosidase activity of A. carbonarius and A. niger was found with 20mmoll(-1) of BHA or PP at 0.98 and 0.95 aW, respectively, whereas for α-d-galactosidase activity a significant decrease in enzyme activity with respect to control was observed in A. carbonarius among 5 to 20mmoll(-1) of BHA or PP in all conditions assayed. Regarding A. niger, the highest percentages of enzyme inhibition activity were found with 20mmoll(-1) of BHA or PP at 0.95 aW and 96h.
The results of this work provide information about the capacity of BHA and PP to inhibit in vitro conditions two of the most important hydrolytic enzymes produced by A. carbonarius and A. niger species.
近年来，食品级抗氧化剂被安全地用作传统杀菌剂的替代品，以控制多种食品和农产品中的真菌生长。
在本研究中，评估了丁基羟基茴香醚（BHA）和对羟基苯甲酸丙酯（PP）在不同水分活度条件（aW；0.98、0.95和0.93）以及孵育时间间隔（24、48、72和96小时）下，对基于花生的培养基上黑曲霉属物种的两种水解酶活性（β-d-葡萄糖苷酶和α-d-半乳糖苷酶）的影响。
分别以4-硝基苯基-β-d-吡喃葡萄糖苷和4-硝基苯基-α-d-吡喃半乳糖苷为底物，测定两种糖苷酶（β-d-葡萄糖苷酶和α-d-半乳糖苷酶）的活性。通过底物酶促水解释放对硝基苯酚导致的405nm处光密度增加来测定酶活性。酶活性以每分钟释放的对硝基苯酚微摩尔数表示。
在水分活度为0.98和0.95时，分别用20mmol/L的BHA或PP可使黑曲霉和黑曲霉的β-d-葡萄糖苷酶活性受到主要抑制，而对于α-d-半乳糖苷酶活性，在所有测定条件下，当BHA或PP浓度在5至20mmol/L之间时，黑曲霉的酶活性相对于对照均显著降低。对于黑曲霉，在水分活度为0.95且孵育96小时时，用20mmol/L的BHA或PP可观察到最高的酶抑制活性百分比。
本研究结果提供了有关BHA和PP在体外条件下抑制黑曲霉和黑曲霉物种产生的两种最重要水解酶的能力的信息。
