EFFECTS OF GAMMA IRRADIATION ON ANTIOXIDANT MARKERS, MICROBIAL POPULATION AND SENSORY ATTRIBUTES OF STRAWBERRY (Fragaria × ananassa Duch.) cv. Festival
FARZANA MRIDHA
Department of Botany, Faculty of Biological Sciences, Jahangirnagar University, Savar, Dhaka 1342, Bangladesh
ROKSANA HUQUE
Food Technology Division, Institute of Food and Radiation Biology, Atomic Energy Research Establishment, Savar, Dhaka, Bangladesh
AFIFA KHATUN
Food Technology Division, Institute of Food and Radiation Biology, Atomic Energy Research Establishment, Savar, Dhaka, Bangladesh
MAHFUZA ISLAM
Food Technology Division, Institute of Food and Radiation Biology, Atomic Energy Research Establishment, Savar, Dhaka, Bangladesh
ARZINA HOSSAIN
Food Technology Division, Institute of Food and Radiation Biology, Atomic Energy Research Establishment, Savar, Dhaka, Bangladesh
MD. AFZAL HOSSAIN
Food Technology Division, Institute of Food and Radiation Biology, Atomic Energy Research Establishment, Savar, Dhaka, Bangladesh
MD. SHAHINUR KABIR *
Food Technology Division, Institute of Food and Radiation Biology, Atomic Energy Research Establishment, Savar, Dhaka, Bangladesh
*Author to whom correspondence should be addressed.
Abstract
Gamma irradiation has emerged as one of the safe alternative methods for decontamination of different types of fruits. A study was carried out to assess the effects of different doses of gamma irradiation (0.5, 1.0 and 1.5 kGy) on the antioxidant markers, microbial population and sensory attributes of strawberry (Fragaria × ananassa Duch. cv. Festival). The physico-chemical attributes and microbial population of the gamma irradiated and control (non-irradiated) strawberries were observed for 6 days. The average concentrations of ascorbic acid (AA), total phenolics (TP) and total flavonoids (TF) were 185.30±13.94 mg/100 g, 193.64±2.32 mg GAE/100 g and 271.67±9.44 mg QE/100 g, respectively in fresh non-irradiated strawberry samples. Application of gamma radiation caused increase of TP and TF contents but decrease of AA content. During storage, a decrease of TF content was observed in the non-irradiated samples. The total viable bacterial count (TVBC), total yeast and mold count (TYMC) and total coliform count (TCC) were 6.2×104cfu/g, 3.0×103 cfu/g and 1.6×103 cfu/g, respectively in fresh strawberry fruits. In the irradiated samples, microbial counts decreased in dose depended manner. Application of 1.5 kGy irradiation caused about 2.5 log reduction of TVBC and about 1.0 log reduction of TYMC. Furthermore, 1.5 kGy gamma irradiation prevented at least 2 log TVBC increase observed in non-irradiated samples after 6 days of storage. The study revealed that the non-irradiated strawberry (cv. Festival) spoiled completely within 6 days of storage whereas the samples which received 1.5 kGy gamma radiation remained acceptable based on the content of antioxidant markers, microbial population and sensory attributes.
Keywords: Strawberry, gamma irradiation, antioxidant, microbes, shelf life