EFFECT OF FRUCOL APPLICATION ON SHELF LIVE OF IDARED APPLES Viorica Chitu, Emil Chitu, Florin-Cristian Marin Research Institute for Fruit Growing, Pitesti, Romania. Abstract The paper present the results obtained after Frucol product application on apple and its effect on shelf live of 'Idared' cv. fruits. The experiment was conducted between 2003-2005, at RIFG Pitesti-Maracineni. In order to evaluate the apples behavior during their storage period, fruits were harvested at full ripening time. To form average samples, fruit were picked up from the top, middle and bottom of the trees, both from the sunny and shady canopy sides. The samples were collected from a trial treated with Frucol conc. 0.5% in vegetative stage and stored for 180 days at a temperature of 3.6º C and at a relative humidity value of 66.8 %. During the experiment, the fruits physical indicators like size, weight, colour and firmness as well as the physiological and biochemical parameters were monitored. The readings were carried out at 1 day, 90 days and 180 days after the harvest moment. Visually, the causes for fruit breakdown and storage diseases and physiological disorders were assessed. The apples treated with Frucol conc. 0.5% had a better shelf life; after 180 days storage period. only 5% of apples were affected by storage diseases, mainly. Alternaria spp. and only 9% of them were damaged by brown-core physiological disorder, compared with 17% diseased fruits and 12% fruits damaged by brown-core disorder in untreated control. Keywords: Malus x domestica, storage time,fruit quality, diseases, physiological disorder 1.Introduction Management of harvesting operation, can have a major impact on the quality of apple fruits during the storage period (Wils, 1998; Kader, 2002). To get a idea of the characteristics of ripening expressed in different parameters, we made a series with picking stages from unripe to overripe fruits (Bloksma J., 2001; Streif, 1996). The storage management concept includes the packing of fruits, the temperature and air relative humidity, microbial contamination and storage disorder evaluation (Kader, 2002; Lotze et al., 2007; Pham et al., 2007; Hyde, 2001; Glen, 1990; Sams, 1990; Snowden, 1990; Thompson, 1996). The objective of this paper is to determine the influence of storage conditions, on apple fruit quality in 'Idared' cv. 2.Material and methods To evaluate the apple fruit quality during the storage period, apple samples ('Idared' cv.) were harvested at the ripening time. The fruit average sample included apples picked from the top, bottom and mid of the crown, totally 90 apples (30+30+30). The fruits were harvested from an orchard treated with a product with multiple function (Frucol -nutrient and fungicide too), applied four times in the growing season with 0,5% concentration). Average weight, firmness on the 2 diameters, ph, dry weight, temperature (3.6 C) and also relative air humidity (67%) in the storage chamber were recorded. The observations were performed as follows: 1 day, 90 days and 180 days after harvesting. They were carried out in laboratory after 1 day from picking, and for time left from the storage warehouse in two different periods. The firmness was determined by means of analogical penetrometer, and ph and dry matter content were determined using digital lab devices. Simultaneously, the fruit damage level was evaluated. The storage diseases and their physiological cause which led to the fruit damage were visually observed. That was done on average samples of 100 fruits. The results were inserted and organized using MS Excel 7 tools and assessed using Duncan's multiple range test and correlation coefficients. 120
Results and discussions Over the fruit storage period, firmness and chemical composition analyses were performed. Figure 1 shows the results obtained in 3 various moments. Fig. 1. Variation of the main physical and chemical indicators of 'Idared' apples during the storage period It is revealed, that the mean firmness at the harvesting time and 90 days after it, is not significantly different from the firmness at 180 days after harvesting. There are also major differences between the fruit dry matter content after one day, 90 and 180 days after picking (12.8% down to 9.3-9.9%). The difference regarding the fruit dry mater content between 90 or 180 days moments is not significant. The fruit ph has significant differences at 90 days and 180 days, after picking. The observations performed over three various moments showed that the most important indicator for the fruit quality at storage time was the firmness. Analyzing the determination coefficient between those indicators presented in figure 2, we can see a significant negative correlation between the fruit mean weight and fruit firmness over the two moments of determination 90 days (r 2 =0.500***) and 180 days (r 2 =0.342**) of storage, respectively. Apple fruit ph content changes during storage time. Figure 3 shows a positive correlation between the mean fruit weight and fruit flesh ph at 90 days after picking (r 2 =0.163) and 180 days (r 2 =0.182*). Variation of the fruit flesh ph during the storage is connected to the biochemistry. Analyzing the apple dry matter content, we found a positive significant correlation coefficient for the whole storage time and significant differences among all the 3 moments of data found (Fig. 1). Fig. 2. Correlations between fruits weight and firmness for 'Idared' cv. 121
Fig. 3. Correlations between the fruit weight and fruit flesh ph for 'Idared' cv. Fig. 4. Correlations between the fruit weight and soluble dry matter in flesh juice for 'Idared' cv. In figure 4 one can see the positive correlation between the two most important indicators: the fruit mean weight and dry matter of flesh juice. We found a positive correlation only at 90 days after harvesting (r 2 = 0.417**). We did not find any significant correlation between fruit firmness and fruit flesh ph for each moment of determination (1; 90 and 180 days storage period), (Fig. 5). 122
Fig. 5. Correlations between the fruit firmness and fruit flesh ph for 'Idared' cv. The most intense negative correlation for the 90 days of storage was found between the fruit firmness and dry matter of fruit juice (r 2 = 0.573***) (Fig. 6). Fig. 6. Correlations between fruit firmness and dry matter of fruit juice for 'Idared' cv. For 180 days of storage, we did not found any positive or negative correlation between those indicators because the dry matter from flesh juice moved into the flesh after the biochemistry transformation. A statistical positive correlation between the fruit flesh ph and dry matter in juice fruit occurred only at 1 day after harvesting (r 2 =0.168*) (Fig 7). 123
Fig. 7. Correlations between the fruit flesh juice ph and soluble dry matter for 'Idared' cv. A significantly positive correlated was obtained for the entire period between those indicators. In figure 8, the effect of Frucol product on 'Idared' apples is illustrated in relation with the storage diseases and physiological disorders. Fig. 8. The effect of the Frucol product on 'Idared' apples in relation with the storage diseases and physiological disorders The apples treated with Frucol, conc. 0.5%, had a better shelf life after 180 days storage period. Only 5% of apples were affected by storage diseases, mainly, Alternaria spp. and only 9% of them were damaged by brown-core physiological disorder, compared with 17% diseased fruits and 12% fruits damaged by browncore disorder in the untreated control treatment. 124
4.Conclusions The observation performed over three various moments showed that the most important indicator for the fruit quality for storage was the fruit firmness. A negative significant correlation was found between fruit weight and fruit firmness at 90 and 180 storage days. No significant correlation between the mean fruit weight and fruit flesh ph was found, nor between fruit firmness and fruit flesh ph, and fruit flesh ph and dry matter juice content. A significant negative correlation was found between the fruit firmness and dry matter of flesh juice at 90 days after harvesting. References Block Joke S.M.A., 2001, Parameters for apple quality, Louis Bulk Institute, 2001 Part One Report; Chu George, 1993, Strategies and alternative to reduce apple crop loss from storage scal disorder, Grower magazine Fruit and Vegetable (Growers Association Ontario); Glen G.M., Poovaiah B.W., 1990, Calcium mediated post -harvest changes in texture and cell wall structure and composition in Golden Delicious apples at Journal of the American Society for Horticultural Science 115,962-963; Hyde G.M., Bartelle A.L. and Vartih J., 2001, Conditioning to reduce impact Bruising in fruits and vegetables, WSU TEREC- Postharvest Information Network Washington State University, 1-5; Jonston J.W., Errol W. Hewett, Martin A.T.M. Hertog, 2002, Postharvest softening of apple (Malus x domestica) fruit a review. New Zealand Journal of crop and Horticultural Science vol. 30,145-160; Kader A.A., 2002, Post-harvest tehnology of horticultural crops.oakland Unifersity of California, Division of Agriculture and Natural Resources Publication 3311,535 pp. Lotze E. and Theron K.I., 2007, Improving the prediction model for harvest maturity of Forelle pears. Abstracts of the 8 th International Symposium on Modelling in Fruit Research and Orchard Management. Einsiedeln, Switzerland, 1-5 July 2007: 56; Sams E.C., 1990, Preharves factor affecting postharvest texture Postharvest Biology and Tehnology no 15,249-254. Snowden A.L., 1990, A colour atlas of post-harvest diseases and disorder of fruit and vegetables Vol.1 general introduction and fruits Boca Raton,FL;CRC press,302 pp Streif J., 1996, Optimun harvest date for different apple cultivars in the Bodensee area p.15-20 in A de Jager D., Jonson and E.Holm editure Luxemburg. Pham T.V., McConchie R., Morris S., Tanner D., Herbert R., 2007, Prediction of changes in firmness of Pink Lady apple during storage. Abstracts of the 8 th International Symposium on Modelling in Fruit Research and Orchard Management. Einsiedeln, Switzerland, 1-5 July 2007: 54; Wils R. B., McGlasson D., Graham and Joyce D., 1998, Postharvest An introduction to the physiology and handling of fruit,vegetables and ornamentals> Waliinford CAB International, 262 pp. 125