|Obenland, David - Dave|
|CANTWELL, MARITA - University Of California|
|LOBO, RAMIRO - University Of California|
|COLLIN, SUE - University Of California|
|SIEVERT, JIM - University Of California|
|ARPAIA, MARY LU - University Of California|
Submitted to: Scientia Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/11/2015
Publication Date: 12/28/2015
Citation: Obenland, D.M., Cantwell, M., Lobo, R., Collin, S., Sievert, J., Arpaia, M. 2016. Impact of storage conditions and variety on quality attributes and aroma volatiles of pitahaya (Hylocereus spp.). Scientia Horticulturae. 199:15-22.
Interpretive Summary: Pitahaya, also called dragon fruit, is a fruit crop increasing in popularity but knowledge on the effects of storage and the potential impact of variety on subsequent quality following storage is incomplete, particularly in terms of the potential effect on flavor. In this study six varieties of pitahaya were evaluated for flavor, appearance, and other quality attributes at harvest and following storage for two weeks at either 5°C or 10°C. Sensory panelists were not able to determine any effect of storage on the appearance of the fruit or of its flavor. This was true even though the amount of sugar, acid, and aroma compounds in the flesh changed as a result of storage. Antioxidant activity was slightly reduced by storage at 5ºC but not at 10ºC. Sensory panelists preferred some varieties over others with the key factors determining this being sweetness and degree of flavor. Aroma volatiles differed among the varieties but there was no obvious link between the volatiles and flavor quality. Varieties with colored flesh had the highest levels of antioxidant activity. This study determined that storage caused measureable changes in a range of important quality parameters but that these changes did not substantially alter the sensory quality of the fruit. The findings are important in the development of proper storage protocols to maintain quality and marketability of pitahayas after harvest.
Technical Abstract: Pitahaya are increasing in popularity but knowledge on the effects of storage and the potential impact of variety on subsequent quality following storage is incomplete, particularly in terms of the potential effects on sensory acceptability. In this study six varieties of pitahaya, having white, pink, and red internal flesh coloration, were harvested and evaluated for sensory and quality attributes at harvest and following storage for two weeks at either 5°C or 10°C. Storage did not influence overall visual likeability or color of the external portion of the fruit as discerned by the panelists. Alterations in the internal flesh color, such as a slight darkening, were noted to occur by instrumental measurement, but these differences were not noticeable to the panelists. Losses in sugars and acids occurred in the flesh during storage at both storage temperatures and were related to declines in fructose, glucose and malic acid. In contrast, antioxidant activity was reduced by storage at 5°C but was unchanged at 10°C, with betacyanin concentration not differing from that determined at harvest. Aldehydes were the most abundant aroma volatiles detected in juice from the flesh, with storage increasing total aldehyde amount, particularly at 10°C. Total alcohols, on the other hand, were reduced by storage, and the amount of reduction was not dependent on storage temperature. Regardless of the storage-induced changes in the various components measured, panelists did not report any significant differences in overall liking, flavor, sweetness, tartness or texture. There were substantial varietal differences in sensory and quality attributes, regardless of the impact of storage. ‘Cebra’ had very low sweetness relative to the other varieties and had low flavor and overall likeability scores. Panelist perception of flavor quality was not clearly linked with varietal differences in sugars, acids or aroma volatiles. Mexicana, a white-fleshed variety, had the lowest antioxidant activity, corresponding to low amounts of the red betacyanin pigments. The study indicated that storage, and particularly that at 10°C, caused a variety of measureable changes in a range of pitahaya quality parameters but that these changes did not substantially alter the sensory quality of the fruit. Further research is needed to determine whether or not varietal or storage-induced differences in aroma volatile content have an impact on pitahaya flavor.