VOLATILE PROFILING OF HOT WATER DIPPED APPLES
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VOLATILE PROFILING OF HOT WATER DIPPED APPLES Introduction Hot water dipping (HWD) has been proven successful to reduce storage rot in apples. However, excessive heat during dipping easily induces heat stress and physiological disorders which first show up after several weeks in cold storage (Fig. 1). A method for early detection of physiolo- gical disorders is desirable to further develop the technology for HWD of apples. Apples emit volatile organic compounds (VOCs) during ripening which may be used as indicators for heat stress in HWD apples. The aim was to develop an analytical method for VOC profiling of ap- ples dipped in hot water for future use in early detection of physiological disorders in apples. Martin Himmelboe 1* , Alexandru Luca 1 , Renata de Paulo Rocha 2 , Marianne G. Bertelsen 1 and Merete Edelenbos 1 1 Department of Food Science, Aarhus University, Kirstinebjergvej 10, 5792 Årslev, Denmark 2 Departamento de Ciência dos Alimentos, Federal University of Lavras, 37200-000 Lavras, MG, Brazil AARHUS UNIVERSITY [email protected] Tel: +45 87158384 Results/Discussion Treatment with 56 °C water for 3 minutes resulted in physiological disorders in all apples (Fig. 1) while no disorders were seen in apples treated with 20 °C water (Fig. 1). A total of 54 compounds were found using solid-phase micro- extraction of which all were incorporated into the SIM program. Using the SIM program 27 VOCs representing 9 chemical groups could be detected in the static headspace samples including ethylene which was detected by the flame ionization detector. There were marked differences in the VOC profiles of the cultivars and between treat- ments. Butyl butanoate and hexyl ethanoate were produced in larger quantities at 20 °C than at 56 °C (Fig. 2A). The opposite was seen for methanol and ethanal which were produced in larger quantities after HWD at 56 °C (Fig. 2B). Conclusions The developed method allowed for volatile profiling of apples treated with hot water. Several compounds seem to be associated with hot water dipping at a damaging temperature thus indicating that volatile profiling could be used for early detection of physiological disorders of hot water dipped apples. Material and Methods Apples of cultivars Ingrid Marie and Pinova were dipped in water at 20 °C and 56 °C for 3 minutes and subsequently dried 20 min in ventilated air. For VOC analysis, apples were taken directly after drying. Physiological disorders were evaluated on apples stored at 2 °C for 8 and 14 weeks . VOC analysis. Apples were placed in airtight jars and left for 2 hours at 20 °C before VOCs were sampled by solid- phase micro-extraction and static headspace sampling. VOCs from solid-phase micro-extraction were analyzed on a gas chromatograph coupled to a mass spectrometer ope- rating in total ion current mode and to a flame ionization detector. From the results, a selected ion monitoring (SIM) program was made. Using this program, VOCs from the static headspace samples were analyzed. Week 0 Week 8 Week 14 Pinova 20 °C 3 minutes Pinova 56 °C 3 minutes Fig. 1. Development of physiological disorders following hot water dipping of pinova apples. Fig. 2. Volatile organic compounds found in the static headspace samples. A. Butyl butanoate and hexyl ethanoate. B. Methanol and ethanal. 7.05 7.10 7.15 7.20 7.25 7.30 7.35 7.40 7.45 7.50 30000 40000 50000 60000 70000 80000 90000 100000 Time -- > Abundance Ethanal Methanol Ingrid Marie, 20 °C Ingrid Marie, 56 °C Pinova, 20 °C Pinova, 56 °C B 20.40 20.60 20.80 21.00 21.20 21.40 --> A Butyl butanoate Hexyl ethanoate 27000 28000 29000 30000 31000 32000 33000 34000 35000 36000 37000 38000 39000 Time Abundance
Transcript of VOLATILE PROFILING OF HOT WATER DIPPED APPLES
VOLATILE PROFILING OF HOT WATER DIPPED APPLES
Introduction
Hot water dipping (HWD) has been proven successful to reduce storage rot in apples. However, excessive heat during dipping easily induces heat stress and physiological disorders which first show up after several weeks in cold storage (Fig. 1). A method for early detection of physiolo-gical disorders is desirable to further develop the technology for HWD of apples. Apples emit volatile organic compounds (VOCs) during ripening which may be used as indicators for heat stress in HWD apples. The aim was to develop an analytical method for VOC profiling of ap-ples dipped in hot water for future use in early detection of physiological disorders in apples.
Martin Himmelboe1*, Alexandru Luca1, Renata de Paulo Rocha2, Marianne G. Bertelsen1 and Merete Edelenbos1
1Department of Food Science, Aarhus University, Kirstinebjergvej 10, 5792 Årslev, Denmark2Departamento de Ciência dos Alimentos, Federal University of Lavras, 37200-000 Lavras, MG, Brazil
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Results/Discussion
Treatment with 56 °C water for 3 minutes resulted in physiological disorders in all apples (Fig. 1) while no disorders were seen in apples treated with 20 °C water (Fig. 1).
A total of 54 compounds were found using solid-phase micro- extraction of which all were incorporated into the SIM program. Using the SIM program 27 VOCs representing 9 chemical groups could be detected in the static headspace samples including ethylene which was detected by the flame ionization detector. There were marked differences in the VOC profiles of the cultivars and between treat-ments. Butyl butanoate and hexyl ethanoate were produced in larger quantities at 20 °C than at 56 °C (Fig. 2A). The opposite was seen for methanol and ethanal which were produced in larger quantities after HWD at 56 °C (Fig. 2B).
Conclusions
The developed method allowed for volatile profiling of apples treated with hot water. Several compounds seem to be associated with hot water dipping at a damaging temperature thus indicating that volatile profiling could be used for early detection of physiological disorders of hot water dipped apples.
Material and Methods
Apples of cultivars Ingrid Marie and Pinova were dipped in water at 20 °C and 56 °C for 3 minutes and subsequently dried 20 min in ventilated air. For VOC analysis, apples were taken directly after drying. Physiological disorders were evaluated on apples stored at 2 °C for 8 and 14 weeks .
VOC analysis. Apples were placed in airtight jars and left for 2 hours at 20 °C before VOCs were sampled by solid- phase micro-extraction and static headspace sampling.
VOCs from solid-phase micro-extraction were analyzed on a gas chromatograph coupled to a mass spectrometer ope-rating in total ion current mode and to a flame ionization detector. From the results, a selected ion monitoring (SIM) program was made. Using this program, VOCs from the static headspace samples were analyzed.
Week 0 Week 8 Week 14
Pinova 20 °C3 minutes
Pinova 56 °C3 minutes
Fig. 1. Development of physiological disorders following hot water dipping of pinova apples. Fig. 2. Volatile organic compounds found in the static headspace samples. A. Butyl butanoate and hexyl ethanoate. B. Methanol and ethanal.
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Butyl butanoate Hexyl ethanoate
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