Fruits physico-chemical parameters of some Romanian kiwifruit hybrids influenced by different cold storage technologies

Abstract

Kiwifruit is recognized as highly nutritious having many biochemical characteristics that deliver a range of health benefits. In Romania, kiwi is a new fruit species and the creation, testing and introduction of winter hardy genotypes, adapted to the local harsh climate conditions is a priority. A common Italian-Romanian kiwifruit breeding program was initiated in 1993 and during the time, several hybrid genotypes were obtained and introduced to be tested. After more than two decades of research, it was demonstrated that Actinidia deliciosa and Actinidia chinensis can be grown in Romania in peach favourable areas, while Actinidia arguta (hardy kiwi, kiwiberry) can cover larger areas, suitable for plum cultivation. At the Faculty of Horticulture within the University of Agronomic Sciences and Veterinary Medicine of Bucharest, an experimental field with kiwifruit hybrid genotypes, was established in 1993. The plants were grown under an organic orchard management, on a T-bar trellis, being irrigated with micro sprayers. The fruits were harvested at beginning of November, in 2017 and 2018. Harvesting moment was established when the fruit flesh firmness was lower than 7.0 kg force cm2. After harvesting, kiwifruits were stored in two different cold storage conditions: normal atmosphere (NA) at 3°C and 95% humidity and controlled atmosphere (CA) with 1.5% Oxygen, at 1-2°C and 95% humidity. The aim of this study was to analyse the fruit quality characteristics of some new kiwi hybrid genotypes at harvest and during storage with the final goal to select best elites. Fruit weight and shape index have been determined after harvest. Different fruit characteristics were measured and evaluated in dynamics: firmness, soluble solids, dry matter, titratable acidity and ascorbic acid. All the determinations and analyses were made at the Research Center for Studies of Food Quality and Agricultural Products laboratories. During the storage, observations showed that R1P9 kiwifruit hybrid presented better biochemical quality parameters and the lowest weight losses compared to the other studied hybrids - 4.69 % in CA and 5.22 % in NA. As expected, keeping kiwi fruits in controlled atmosphere with 1.5% Oxygen, at 1-2°C and 95% humidity, presented better physical and biochemical quality compared with those stored in normal atmosphere, at 3°C and 95% humidity. Using the results of the study regarding the fruits physicochemical characteristics after harvesting and during the storage, but also some other plant parameters, several kiwi hybrid elites were selected - R0P13 and R1P9. They will be propagated and planted for the production test.