The Effect of pH and Temperature on Cabbage Volatiles During Storage

Abstract

During storage of shredded cabbage, characteristic sulfurous volatile compounds are formed affecting cabbage aroma both negatively and positively. Selected ion flow tube-mass spectrometry (SIFT-MS) was used to measure the concentration of cabbage volatiles during storage. The volatile levels of cabbage samples were measured at pH 3.3 to 7.4 at 4 °C for 14 d, and pH 3.3 at 25 °C for 5 d in order to determine the effect of pH and temperature. Aroma intensity, best aroma, freshness, and off odor were evaluated in a sensory test of the samples at 4 °C. The desirable volatile allyl isothiocyanate was lower in high pH samples (pH 7.4 and 6.4), whereas higher concentrations were detected in low pH samples (pH 3.3 and 4.6). Lipoxygenase volatiles, which produce a fresh green and leafy aroma in cabbage, were generated in very low amounts at any pH value. High pH samples generated significantly higher concentrations of off odors such as dimethyl sulfide, dimethyl disulfide, dimethyl trisulfide, and methanethiol. Sensory tests showed that higher pH samples had significantly stronger off odor and lower desirable cabbage aroma than lower pH samples. Thus, sensory results matched the volatile results in that samples at higher pH levels formed the highest amount of undesirable volatiles and the least amount of desirable volatiles. Storage at 25 °C produced similar concentrations of allyl isothiocyanate, but significantly higher levels of off odors, than at 4 °C. Shredded cabbage products should be stored in low pH dressings to minimize formation of off odors and maximize formation of characteristic, desirable cabbage odor.

Methods in plant foliar volatile organic compounds research

“…SIFT-MS is suitable for online monitoring of the major VOCs emitted from plant leaves (Smith and Španěl, 2011; Amelynck et al, 2013; Akpolat and Barringer, 2015). It can be used in different ionization modes (H 3 O + , NO + , or O 2 + ), allowing different qualitative applications.…”

Volatile compounds profiling by using proton transfer reaction‐time of flight‐mass spectrometry (PTR‐ToF‐MS). The case study of dark chocolates organoleptic differences

“…Nevertheless, some food VOC profiling studies are worth mentioning, and improvement of the sensitivity in instruments with reduced size and cost will certainly open new opportunities . Thus, monitoring of processes or storage conditions during shelf life of various foodstuffs was undertaken with SIFT‐MS instruments: cocoa roasting, beef under modified atmosphere packaging, chemical spoilage in retail meat, storage and transformation of various fruits and vegetables, food fermentations, and storage of cabbage . Iberian hams from pigs reared under different conditions could be distinguished based on SIFT‐MS fingerprints, and microbial VOCs were used to identify microorganisms in various foodstuffs spoilage …”

Comprehensive odorant analysis for on‐line applications using selected ion flow tube mass spectrometry (SIFT‐MS)

“…Storage of shredded cabbage results in the formation of such volatiles, which can affect the cabbage aroma negatively or positively. SIFT‐MS analysis of shredded cabbage stored at different pHs and temperatures showed that storage at 25 °C produced significantly higher levels of off‐odours than storage at 4 °C. Low pH storage produced more of the desirable volatile allyl isothiocyanate, while high pH samples generated significantly higher concentrations of off‐odours such as dimethyl sulphide and dimethyl disulphide, indicating overall that low‐pH storage was more favourable.…”