See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/287512682 Response of controlled atmosphere (CA) stored 'Golden Delicious' apples to the treatments with alcohols and aldehydes as... Article · July 2000 CITATIONS READS 13 8 3 authors, including: Jamil Harb Birzeit University 40 PUBLICATIONS 151 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: Organic Farming in Palestine View project All content following this page was uploaded by Jamil Harb on 30 December 2015. The user has requested enhancement of the downloaded file. All in-text references underlined in blue are added to the original document and are linked to publications on ResearchGate, letting you access and read them immediately. Gartenbauwissenschaft, 65 (4). S. 154–161, 2000, ISSN 0016–478X. © Verlag Eugen Ulmer GmbH & Co., Stuttgart Response of Controlled Atmosphere (CA) stored “Golden Delicious” Apples to the Treatments with Alcohols and Aldehydes as Aroma Precursors Reaktion von CA-gelagerten „Golden Delicious” Äpfeln auf die Behandlung mit Alkoholen und Aldehyden als Aromavorstufen J. Harb, J. Streif and F. Bangerth (Institut für Obst-, Gemüse- und Weinbau, Universität Hohenheim, Stuttgart, Germany) Summary Aromastoffe. Sowohl nach ULO-Lagerung wie auch „Golden Delicious” apples were stored under ultra low nach AVG-Behandlung war durch die Behandlung mit oxygen (ULO-storage) and treated both at harvest Aromavorstufen nur eine vorübergehende Wirkung, time and after 5 months of storage with several aroma im allgemeinen von nicht mehr als 2 Tagen, zu beob- precursors. Another plot of fruits was sprayed on the achten. tree with an ethylene inhibitor (AVG) to study the ef- fect of ethylene biosynthesis on volatile production. Introduction ULO-storage caused a marked reduction on the ability of fruit to produce volatiles. Feeding these fruits with Controlled atmosphere (CA) stored apples, especially several alcohols and aldehydes as aroma precursors, sti- those stored under ultra low oxygen (ULO), exhibit a mulated the biosynthesis of volatiles. Each alcohol and diminished capacity to synthesize aroma volatiles. Al- aldehyde led to an enhanced production of the corre- though such apples remain firmer, juicer and greener, sponding volatile, mainly esters. Similar to ULO-stor- the lack of their ability to produce normal rates of vola- age, AVG reduced the production of volatiles and this tiles led to critical acceptance by the consumers (BOH- effect was accentuated during the storage of these fruits LING 1982, LEHMANN 1993). The reasons for this phe- in ULO. Treating AVG-fruit with aroma precursors nomena are still not completely understood. STREIF and also led to a marked increase in the production of the BANGERTH (1988) proved that storage of apples at 1% corresponding volatiles. With ULO stored as well as O2 reduced the biosynthesis of odor volatiles. YAHIA with AVG-treated fruits, the effect of precursor treat- (1991) indicated that a post-storage period of 3 weeks ment on volatiles was transient lasting, in general, not at 3.3 °C after a low ethylene CA-storage did not im- more than 2 days. prove the ability of apples to synthesize volatiles. It is supposed that the reduced biosynthesis of fatty acids, mainly of the unsaturated linolenic and linolic acids, is Zusammenfassung the main reason for the diminished odor volatile pro- „Golden Delicious” Äpfel wurden unter besonders duction (PAILLARD 1990), and this was confirmed by niedrigen Sauerstoffkonzentrationen (ULO-Bedin- reasonable good correlations between the concentra- gungen) gelagert und sowohl bei der Ernte als auch tion of these fatty acids and aroma production (BRACK- nach 5 Monaten Lagerung mit verschiedenen Aroma- MANN et al. 1993). vorstufen behandelt. Ein weiterer Teil der Früchte The aim of this research was to investigate the effect wurde am Baum mit einem Ethyleninhibitor (AVG) of ULO-stored fruits on their ability to synthesize vo- gespritzt, um den Effekt der Ethylenbiosynthese auf latiles and whether the application of particular fatty die Aromabildung zu untersuchen. ULO-Lagerung acid-derived aroma precursors (alcohols, aldehydes, verursachte eine deutliche Verminderung der Aroma- esters, and acids) can improve the biosynthesis of odor- bildung der Früchte. Durch Behandlung solcher volatiles. On the other hand, the relationship between Früchte mit verschiedenen Alkoholen und Aldehyden ethylene biosynthesis and volatile production was als Aromavorstufen konnte die Biosynthese von tested throughout storage of “Golden Delicious” fruits flüchtigen Aromastoffen stimuliert werden. Jeder der treated with AVG on the tree to retard ethylene bio- verwendeten Alkohole und Ester verursachte eine ge- synthesis. steigerte Bildung von entsprechenden Aromastoffen, vor allem von Estern. Ähnlich wie die ULO-Lagerung verminderte die AVG-Behandlung ebenfalls die Bil- Material and Methods dung flüchtiger Aromastoffe, wobei diese Wirkung The experiments were done in two consecutive years. durch CA-Lagerung noch verstärkt wurde. Auch bei “Golden Delicious” apple fruits were harvested in the den mit Aromavorstufen behandelten AVG-Früchten orchards of the Experimental Station of Hohenheim erfolgte eine gesteigerte Bildung der entsprechenden University at Bavendorf, Germany. Fruits were brought Gartenbauwissenschaft 4/2000 Harb, J. et al.: Aromastoffbildung bei CA-gelagerten Äpfeln 155 Fig. 1. The influence of different storage conditions on total aroma production of ‘Golden Delicious’ apples. Einfluß der Lagerbedingungen auf die Gesamtaromabildung von “Gol- den Delicious” Äpfeln. at the same day into ULO conditions at 3% CO2 + 1% spaces of the fruit. After treatment, the fruits were kept O2; 1 °C and 93% R.H.. Directly after harvest and at under 20 °C and flushed continually with normal air. two-months intervals during the subsequent storage At the first and seventh day after the application of period, aroma production was determined adopting the precursors, the volatiles of 50 l of the head-space air method of volatiles adsorption on small quantities of were adsorbed by inserting a Tenax AT column (60/80 charcoal as described by STREIF (1981). In an other ex- mesh) into the outcoming air-stream of the conti- periment ‘Golden Delicious’ trees were sprayed with nuously ventilated fruits. 25 ml diethyl ether plus 1 ml aminoethoxyvinyl glycin (AVG), an inhibitor of ethyle- of an internal standard solution (500 ppm hexyl methyl- ne biosynthesis, at a concentration of 200 mg/l. The keton in pentane) were used to extract the adsorbed trees were sprayed 4 times at weekly intervals starting odor volatiles from the Tenax columns. Thereafter the one month before harvest. These fruits were also stored final volume of the extract solution was reduced to under the above conditions and subjected to the same 0.3 ml under N2 gas stream. (A more detailed descrip- treatments. tion of the method was published previously by SONG Directly after harvest and after 6-months of storage, and BANGERTH 1996). 1 µl from this final extract solu- several aroma precursors (see Table 2) were applied se- tion was injected into a capillary GC: Detector: FID; parately to the fruits. Within each treatment, 10 fruits column: 25m × 0.32 mm, ID fused silica CW 20M- DF- were enclosed in 10 l desiccators and evacuated to 50-80 0.25; carrier gas: N2; injector temperature: 240 °C; de- mbar. Each aroma precursor (0.1–0.15 ml) was injected tector temperature: 260 °C; temperature program for into the evacuated desiccator, where it quickly evapo- the column: 3 min. at 35 °C, 35–100 at 5 °C/min., rated. That creates a concentration of 5–7.5 ppm of 100–180 at 6 °C/min., 10 min. at 180 °C. each precursor. The pressure within the desiccator was A factor that represents the relative change of each released to ambient value within 25 min. Release of the odor-volatile was calculated based on the peak area of partial vacuum caused a better and more uniform distri- the standard. This factor was termed “r-factor”. It com- bution of the precursors within the intercellular air prises the peak area of a particular odor volatile after the Fig. 2. Composition of aroma spec- trum (%) of ‘Golden Delicious’ ap- ples, directly after harvest (Octo- ber) and after 7 months storage pe- riod (April) under different condi- tions. Prozentuale Zusammensetzung des Aromas von „Golden Delicious“ un- mittelbar nach der Ernte (Oktober) und nach 7-monatiger Lagerung (April) bei unterschiedlichen Lagerbe- dingungen. Gartenbauwissenschaft 4/2000 156 Harb, J. et al.: Aromastoffbildung bei CA-gelagerten Äpfeln Table 1. Composition of aroma spectrum (arbitrary peak area Table 2. The influence of feeding butanol to “Golden Deli- units) of AVG-treated and control “Golden Delicious” ap- cious” apples, either directly after harvest (Oktober) or after ples, directly after harvest (October) and after 5 months in 5 months under ULO-storage (March), on the synthesis of ULO-storage (March). particular aroma components. Measurements were done 1 day Zusammensetzung des Aroma-Spektrums (angegeben als Peak- after feeding and 7 days after feeding. Explanation for r-fac- fläche-Einheiten) von „Golden Delicious“ Äpfeln direkt nach tor: see materials and methods. der Ernte (Oktober) und nach 5 Monaten ULO-Lagerung Der Einfluss einer Begasung mit Butanol von “Golden Deli- (März) mit und ohne AVG-Behandlung. cious" Äpfeln sofort nach der Ernte (October) oder nach 5 Mo- naten ULO-Lagerung (März) auf