Abstract

CALDERON-GABALDON, María; RAYBAUDI-MASSILIA, Rosa; MOSQUEDA-MELGAR, Jonathan  and  TAPIA, María. Effect of UV-C light and malic acid on Rhodotorula glutinis and shelf-life of fresh-cut ‘Maradol’ papaya. Bioagro [online]. 2012, vol.24, n.2, pp.103-114. ISSN 1316-3361.

The effect of different doses of UV-C light and malic acid on Rhodotorula glutinis (predominant spoilage flora) inoculated on pieces of ‘Maradol’ papaya was studied. Fresh-cut papayas were dipped into solutions containing malic acid (0, 0.5, 1.0, and 1.5%), calcium lactate (1%) and ascorbic acid (0.5%) by 1 min. Afterward, the samples were inoculated on their surfaces with a pure culture of R. glutinis (10⁷ UFC·g^-1), and then treated with UV-C light (0, 0.96, 2.88, 5.76 y 8.64 kJ/m²). Significant differences (Pp≤0.05) among counts of R. glutinis on treated fresh-cut papaya were observed. A higher inactivation (6.3 log UFC/g) was found when 1.5% malic acid and a dose of UV-C light of 8.64 kJ/m² were used. This combination was used to assess the effect on the microbiological and physicochemical shelf-life extension, as well as on sensory attributes of pieces of papaya. A significant inhibition of the growth of populations of aerobic mesophilic, psychrophilic, molds, and yeasts; as well as maintenance of physico-chemical properties such as color and firmness during storage for 16 days at 5 ºC was observed. Likewise, the sensory evaluation of fresh-cut papaya treated, showed no significant differences (p>0.05) in comparison with control samples. These results showed that UV-C light in combination with stabilizer substances such as malic acid, calcium lactate and ascorbic acid can be a good alternative in the preservation of fresh-cut fruits.

Keywords : Sensory attributes; microbiological parameters; stabilizer substances.