Hot water treatments performed in the base of the broccoli stem reduce postharvest senescence of broccoli (Brassica oleracea L. Var italic) heads stored at 20 °C

Abstract

Heat treatments cause a moderate and reversible stress that interrupts the normal metabolism (senescence or fruit ripening) of the product. Although there is a large number of reports about heat treatments on broccoli heads, the effect of subjecting only the stems to thermal treatments has not been studied yet. One of the main reasons to analyze this approach is that the hormone ethylene is actively produced in the stem cutting area.Different hot water treatments were performed on the first 5 cm of broccoli stems with various combinations of time-temperature. Treatment carried out at 50 C for 3 min was chosen for further analysis of different quality and senescence parameters, taking into account that broccoli heads presented a delayed change in Hue and L values when compared with controls during storage. While control heads looked yellow, heat-treated samples retained most of their green colour. Furthermore, control heads presented higher weight loss, lower total and soluble protein, and lower total soluble sugar after 3 or 5 storage days, giving evidence of the fact that a heat treatment just on the stem contributes to the delay of broccoli senescence and to the maintenance of the overall quality of the product during storage.

The time of the day to harvest affects the degreening, antioxidant compounds, and protein content during postharvest storage of broccoli

“…Superficial color of broccoli heads was measured according to Perini et al (). Five heads were used per each condition and five measurements were done on each head.…”

“…Extractions of soluble and total proteins were done according to Perini et al (2017). Soluble proteins were quantified by the method of Bradford (1976), whereas total proteins were measured according to Lowry et al (1951).…”

Post-Harvest Treatments and Related Food Quality

“…Hot water treatment at 52 and 56 °C for 20 s up to 2 min can reduce post-harvest decay of apples and citrus fruit caused by Gloeosporium and Penicillium digitatum (Porat et al 2000;Trierweiler et al 2003;Maxin et al 2014). Furthermore, hot water treatments of only parts of vegetables like stems of broccoli can reduce the senescence and preserve the product colour (Perini et al 2017). According to two recent reports (Trierweiler et al 2003;Auinger et al 2005), the basic quality parameters of apples like titratable acidity, antioxidative capacity, total phenolics, and vitamin C are not negatively influenced by hot water treatment.…”

Behaviour of fresh cut broccoli under different modified atmosphere conditions

“…29(3): 188-197 doi: 10.9755/ejfa.2016-07-907 http://www.ejfa.me/ Chaves, 2007), leek (Tsouvaltzis et al, 2006), melon (Luna Guzmán et al, 1999) and garlic (Cantwell et al, 2003). For broccoli, hot air or water can delay senescence in intact heads (Funamoto et al, 2002, Perini et al, 2017 and in fresh-cut product (Lemoine et al, 2008(Lemoine et al, , 2009Costa et al, 2005).…”