Susceptibility of carrot roots and apple fruits to enzymatic browning processes

The present study of three vegetation periods evaluated the enzymatic browning process of two different commodities, carrot roots and apples. The influence of the genetic potential (effect of genus and cultivar), of magnesium fertilization is case of carrot and of storage (in case of carrot 6 months in a traditional natural mound and in case of apple 6 months under ultra low oxygen (ULO) conditions) were investigated. In the case of carrot 5 different cultivars were investigated, middle late 'Berjo', late: 'Flacoro', 'Karotan', 'Koral', 'Perfekcja', and magnesium doses (0, 45, 90 kg∙ha-1 of MgO) by constant fertilization with nitrogen (70 kg∙ha-1), phosphorus (80 kg∙ha-1 of P2O5), and potassium (100 kg∙ha-1 of K2O). In October harvested roots were stored for 6 months in the traditional natural mound. In the case of apple fruits seven different cultivars were used: 'Elstar', 'Gloster', 'Honeygold', 'Idared', 'Jonagored', 'Ligol', and 'Szampion', from the commercial Agricultural and Fruit Farm Klimkiewicz, Wtelno (Kuyavian-Pomeranian Voivodeship) using integrated horticulture production procedures. Apple fruits were stored under ULO conditions for 6 months (>2% O2, <2% CO2, 1.5-2.0°C and 95-96% RH). Susceptibility of commodities was evaluated directly after harvest and after the 6 months of storage using collorimetrically determination method at 475 nm. The evaluation of the enzymatic browning process in carrot roots and apple fruits revealed significant dependency on the used plant material (genus). Carrot roots were generally less susceptible to enzymatic browning compared to the apple fruits. Leaf application of magnesium fertilization, especially at the dose of 90 kg MgO per 1 ha inhibited the browning process. Storage time of 6 months in the mound promoted discoloration of carrot roots and thus negatively influenced their quality. In the case of apple fruits the appropriate choice of cultivar was most important for limiting the enzymatic browning process, which is especially important when selecting raw material for juice production. A low susceptibility to enzymatic browning was found in fruits of cv. 'Elstar', whereas the cv. 'Honeygold' was most susceptible. Changes in the susceptibility to the browning processes of fruit flesh after storage were statistically significant, however quite small in comparison to the values measured directly after harvest.

Przedstawione trzyletnie doświadczenia dotyczyły oceny procesów ciemnienia dwóch różnych rodzajów produktu, korzeni marchwi (5 odmian) i jabłek (7 odmian). Przebadano wpływ potencjału genetycznego (wpływ rodzaju i odmiany), nalistnego nawożenia magnezem (45 i 90 kg∙ha-1) u marchwi oraz przechowywania (w przypadku marchwi tradycyjne kopcowanie przez 6 miesięcy, a w przypadku jabłek 6 miesięcy w warunkach ULO, czyli >2% O2, <2% CO2, 1.5-2.0°C oraz 95-96% wilgotności względnej. Przeprowadzona ocena wykazała, że procesy ciemnienia w korzeniach marchwi i owocach jabłoni zależały od gatunku. Korzenie marchwi podlegały mniej procesom ciemnienia, przy czym nalistne nawożenie magnezem ograniczało ciemnienie, a przechowywanie sprzyjało temu procesowi. W przypadku jabłek dobór odmiany stanowił najważniejszy czynnik w ograniczeniu procesów ciemnienia, co odgrywa znaczącą rolę w wyborze surowca do produkcji soków czy suszu jabłkowego. Ponadto podczas przechowywania zwiększało się ciemnienie, ale mniej w porównaniu do korzeni marchwi.