Effects of different defrosting methods on the stability of bioactive compounds and consumer acceptability of frozen broccoli

Abstract

(2015) Effects of different defrosting methods on the stability of bioactive compounds and consumer acceptability of frozen broccoli, CyTA -Journal of Food, 13:2, 312-320, DOI: 10.1080DOI: 10. /19476337.2014 To link to this article: https://doi.org/10. 1080/19476337.2014 Broccoli (Brassica oleracea var. italica) is an excellent source of bioactive compounds. Frequently, it is commercialized frozen, though it has to be thawed before consumption. However, defrosting methods can affect the nutritional and sensory properties of broccoli. Therefore, the effect of defrosting (microwaving and boiling) for serving broccoli either cold or hot on the content of bioactive compounds (vitamin C, carotenoids, phenolic compounds, and glucosinolates) and sensory acceptability of frozen broccoli was studied. Marked losses of hydrosoluble compounds were observed after boiling. Carotenoids increased after short-time boiling (~20%) but dramatically decreased after microwave-defrosting (between 30% and 40% less). Nevertheless, short defrosting using microwave showed the less overall losses. Moreover, microwave-based methods were preferred by consumers. Microwave-defrosting of broccoli for a short period of time may be the method of choice for better retention of bioactive compounds and organoleptic properties.Keywords: Brassica oleracea var. italica; glucosinolates; vitamin C; carotenoids; phenolic compounds El brócoli (Brassica oleracea var. italica) es una excelente fuente de compuestos bioactivos. Frecuentemente, es comercializado congelado, aunque debe ser descongelado antes de ser consumido. No obstante, los métodos de descongelación pueden afectar las propiedades nutritivas y sensoriales del brócoli congelado. Por consiguiente, el efecto del descongelamiento (microondas y hervido) para servir brócoli frío o caliente en el contenido de compuestos bioactivos (vitamina C, carotenoides, compuestos fenólicos y glucosinolatos) y la aceptabilidad sensorial del brócoli congelado fue estudiado. Pérdidas marcadas de compuestos hidrosolubles fueron observadas después de hervir. Los carotenoides incrementaron después de hervir por tiempo corto (~20%) pero decrecieron después de la descongelación por microondas (entre 30% y 40% menos). Sin embargo, el descogelamiento corto utilizando microondas mostró las menores pérdidas globales. Además, los métodos por microondas fueron preferidos por los consumidores. El descongelamiento corto por microondas puede ser el método de elección para una mejor retención de nutracéuticos y propiedades organolépticas del brócoli congelado.

UVA, UVB Light, and Methyl Jasmonate, Alone or Combined, Redirect the Biosynthesis of Glucosinolates, Phenolics, Carotenoids, and Chlorophylls in Broccoli Sprouts

“…Two carotenoids, the xanthophylls lutein and neoxanthin, were identified within the samples, whereas chlorophyll a and chlorophyll b were also found ( Table 5 ). The carotenoid/chlorophyll chromatogram of broccoli sprouts is similar to those reported in literature for broccoli florets and broccoli sprouts [ 18 , 46 ]. In consistency with Kopsell and Sams [ 46 ], chlorophyll b was the most abundant photosynthetic pigment found in broccoli sprouts samples, while lutein is usually attributed as the major xanthophyll in broccoli florets [ 17 , 18 ].…”

“…The carotenoid/chlorophyll chromatogram of broccoli sprouts is similar to those reported in literature for broccoli florets and broccoli sprouts [ 18 , 46 ]. In consistency with Kopsell and Sams [ 46 ], chlorophyll b was the most abundant photosynthetic pigment found in broccoli sprouts samples, while lutein is usually attributed as the major xanthophyll in broccoli florets [ 17 , 18 ]. Likewise, Kopsell and Sams [ 46 ] also agree that neoxanthin is the major light-harvesting xanthophyll present in broccoli sprouts, although they were able to quantify small levels of violaxanthin, antheraxanthin, and zeaxanthin in their 19-day-old sprouts.…”

“…Total elution time was 35 min at a constant flow rate of 0.5 mL/min. Carotenoids and chlorophylls were detected at 450 nm, and identified by comparing their retention times and absorption spectra with reference standards or previous reports [ 18 , 49 , 50 , 51 ]. Xanthophylls were quantified using a calibration curve of lutein standard (0–12 ppm), and expressed as mg of lutein equivalents per kg of broccoli sprouts DW.…”

“… Abbreviations: shoulder (sh). a Identification of each peak was performed by ( A ) Comparison with the retention time and wavelengths of maximum absorption in the UV/Vis spectra of commercial standards; ( B ) identification by spectral interpretation of the wavelengths of maximum absorption in the UV/Vis spectra and comparison with wavelengths of maximum absorption reported in the literature [ 17 , 18 , 47 , 48 , 49 , 50 ]; and ( C ) identification by the order of chromatographic elution reported in the literature [ 17 , 18 , 49 , 50 , 51 ]. …”

“…Carotenoids are pigments of isoprenoid origin synthesized as secondary metabolites by all photosynthetic organisms such as plants, as they play essential biological roles in light energy collection and protecting the photosynthetic apparatus from photo-oxidative damage [ 16 ]. β-carotene and the xanthophylls lutein, zeaxanthin, violaxanthin, neoxanthin, and β-cryptoxanthin are among the major carotenoids found in broccoli [ 17 , 18 ]. Carotenoids show antioxidant and immunomodulation activities, which may prevent degenerative diseases, such as cardiovascular diseases, UV-induced skin damage, cataracts and macular degeneration, diabetes, and several types of cancer, especially prostate and digestive-tract tumors [ 16 , 19 ].…”