A new strategy to assess the quality of broccoli (Brassica oleracea L. italica) based on enzymatic changes and volatile mass ion profile using Proton Transfer Reaction Mass Spectrometry (PTR-MS)

Investigation of Volatiles Emitted from Freshly Cut Onions (Allium cepa L.) by Real Time Proton-Transfer Reaction-Mass Spectrometry (PTR-MS)

“…These findings suggest that the time from cutting to serving of cut onions is important for sensory perception. It is likely that other vegetables show similar dynamics in the emission of volatiles, as is seen in a recent study of broccoli [23] and based on the current study; PTR-MS will be a very useful tool for investigating such dynamics.…”

“…PTR-MS has been used for detection of volatiles from fruits and vegetables i.e. , apples [17,19], berry fruit [20–22] and broccoli [23]. The advantage of real-time monitoring and high time resolution makes PTR-MS an interesting choice for measuring VOCs emitted from freshly cut onion.…”

Monitoring colour, volatiles in the headspace and enzyme activity to assess the quality of broccoli florets (Brassica oleracea L. italica cv. Bellstar and Legacy) during postharvest storage

“…The volatile organic compound composition in the headspace of broccoli florets was measured using proton transfer reaction mass spectrometry (PTR‐MS, Ionicon Analytic, Innsbruck, Austria) as described previously (Raseetha et al ., ) with minor modifications for sample preparation and sample size. The present study did not detach broccoli florets from the broccoli main stalk during storage compared with Raseetha et al .…”

“…The present study did not detach broccoli florets from the broccoli main stalk during storage compared with Raseetha et al . () and avoided severe mechanical wounding before PTR‐MS measurement because it resulted in different profiles of volatiles released compared with undamaged broccoli florets (Raseetha et al ., ) and promoted plant oxidative stress leading to changes in chemical and biochemical composition of broccoli (Raseetha et al ., ). Broccoli florets were randomly collected to obtain small florets (3–4 mm stem diameter) with a final total weight of 25 g and then transferred into 250‐mL glass bottles (Schott Duran, Wertheim, Germany).…”

“…Peroxidase enzyme activity measurement for each enzyme extract solution was carried out in triplicates as described by Raseetha et al . () with minor modifications. The assay mixture consisted of 1.7 mL phosphate buffer (50 m m , pH 6.0 containing 1 m NaCl), 0.2 mL guaiacol (1% w/v in water), 0.1 mL H 2 O 2 (1.5% w/v in water) and 20 μL enzyme extract.…”