Evaluation of potential of gamma radiation as a conservation treatment for blackberry fruits

Abstract

BACKGROUND: Blackberries consumption has been associated with health benefits. However, these fruits present a short shelflife. Thus, food irradiation is a potential alternative technology for conservation of these fruits without use of chemicals. OBJECTIVE: Analyse the potentiality of gamma radiation as a decontamination method for blackberry fruits. METHODS: Fresh packed blackberries were irradiated in a Co-60 source at two doses (1.0 and 1.5 kGy). Bioburden, physical and rheological, sensorial and total soluble content parameters were assessed before irradiation, immediately after and at two days storage time at 4 • C. RESULTS: The characterization of blackberries microbiota point out to an average bioburden value of 10 4 CFU/g and to a microbial population predominantly composed by filamentous fungi. The inactivation studies on the blackberries mesophilic population indicated a limited microbial inactivation (<1 log decimal reduction) for the applied radiation doses, being the surviving population mainly constituted by filamentous fungi and yeast. No effect of irradiation on colour of blackberries was observed. Concerning texture parameters, no significant differences were observed in both fracturability and firmness between non-irradiated and irradiated blackberries immediately after irradiation. In blackberries stored for two days, both parameters were slightly lower in irradiated blackberries, compared to non-irradiated blackberries. The performed sensorial analysis indicated a similar acceptability among irradiated and non-irradiated fruits. CONCLUSION: This work reveals gamma irradiation treatment potential since no major impact was detected on blackberries physical, rheological and sensory attributes. Further studies with longer periods of storage are needed to elucidate the advantages of irradiation as a conservation treatment.

Improvement of microbiological quality, antioxidant content and shelf life of jujube (Ziziphus mauritiana cv. BAU Kul) fruit by gamma irradiation

“…These counts also increased in the irradiated fruits samples but numbers were far below than that of the nonirradiated fruit sample. An increase of the number of microbial loads in 1.0 kGy irradiated fruits of blackberries were also described by Oliveira et al (2013). However, it is noteworthy to mention that microbial counts of irradiated samples increased in a slow rate than that of non-irradiated sample during storage.…”

Trends in maintaining postharvest freshness and quality of Rubus berries

“…Similarly, Oliveira et al. (2013a) have reported that 1.5 kGy gamma radiations reduced loss of fruit firmness for 2 days as opposed to control in “Primark” blackberry fruit. Sensory attributes related to phytochemical levels in harvested fruit are dependent upon the type of material used for producing gamma irradiations.…”

60Co γ‐radiation at low‐dose level alters volatile compounds of blueberry during storage

“…The results showed that radiation had no significant effect on the healthy fruit rate within 7 days. This was consistent with previous studies that irradiation doses up to 1.5 kGy did not result in a major impact on physical and sensory attributes (Oliveira et al ., 2013). After 7 days, the radiated blueberry fruit decayed slower than the blueberry fruit without radiation.…”

“…Low‐medium dose radiation (<5 kGy) was reported to inhibit fruit decay, delay senescence and prolong the storage period by inhibiting membrane lipid peroxidation and respiratory metabolism (Wang & Meng, 2016; Wang et al ., 2017b; Li et al ., 2021; Liu et al ., 2023). A few studies have reported that irradiation at a low‐dose level (up to 3 kGy) had no significant impact on the physical and sensory attributes of blueberry within a short period of storage (Oliveira et al ., 2013; Golding et al ., 2014). Fruit chemical constituents that contribute to flavour quality include sugars, acids and aroma volatiles.…”