![]() ![]() Besides, the scientific information about the effect of exogenous pretreatment before ultrasound drying on the accumulation of bioactive compounds in broccoli is scarce. To produce dried broccoli products with high nutritional value, more efforts are essential to improve the performance of the ultrasound-assisted drying technique to provide a better preservative effect on the broccoli bioactives. It was found that although ultrasound treatment shortened the drying time and lowered the energy consumption, no significant difference in the retention of glucoraphanin and sulforaphane for the air-dried samples in the presence and absence of ultrasound were observed. In one of our previous studies, the airborne-ultrasound assisted air drying of broccoli florets was studied and the quality of dehydrated products was evaluated. ![]() But only a limited studies focused on the metabolism of glucoraphanin and related metabolites under the simultaneous heating and water removeing treatments, liking drying. ![]() Also, the metabolism of glucosinolates in broccoli during preservation and some thermal treatments have also been previously explored. Many studies manifest that ultrasound is an emerging technique to accelerate the convective drying rate of various fruits and vegetables and enhance the quality of dehydrated products, ,. However, an important challenge for the drying of broccoli is to alleviate the loss of nutrients and bioactive substances and prevent deterioration of its quality. Drying is beneficial to prolong the shelf life and is also an important intermediate method to manufacture vegetable powders. On the other hand, the high water content in fresh broccoli affects its quality, stability, and shelf life. Also, sulforaphane, a breakdown product of glucoraphanin, is the most closely linked with the health-beneficial properties of broccoli. ![]() Glucoraphanin is a major glucosinolate in broccoli, making up around 50% of glucosinolates. Many investigations confirm that the anti-cancer effect of broccoli is mainly attributed to products derived from the enzymatic hydrolysis of glucosinolates. Epidemiological studies have exhibited that long-term consumption of broccoli can provide a protective effect on liver steatosis and cardiovascular disease and help reduce the risk of various cancers. italica) is rich in nutrients and bioactive compounds, like vitamins, dietary fibers, phenolics, glucosinolates, and others. Overall, the reported results can enrich the biochemistry knowledge about the transformation of glucoraphanin to sulforaphane in cruciferous vegetables during drying, and the combined VC/melatonin pretreatment and ultrasound drying is conducive to protect bioactive sulforaphane in dehydrated broccoli.Īs an important cruciferous vegetable, broccoli ( Brassica oleracea L. The correlation analysis revealed that the exogenous pretreatment or ultrasound could affect the enzymatic degradation of glucoraphanin and the generation of sulforaphane through weakening the connections of sulforaphane-myrosinase, sulforaphane-VC, and VC-myrosinase. At the end of drying, the sulforaphane content in samples dehydrated by the sequential melatonin (or vitamin C) pretreatment and ultrasound-intensified drying was 14.4% (or 26.5%) higher than only air-dried samples. Both melatonin pretreatment and vitamin C pretreatment showed protective effects on the sulforaphane content and myrosinase activity during the subsequent drying process. Meanwhile, contact sonication could promote the degradation of glucoraphanin. The results showed that compared with direct air drying, the sequential exogenous pretreatment and contact ultrasound drying shortened the drying time by 19.0–22.7%. To understand the influences of the studied dehydration methods on the conversion of glucoraphanin to bioactive sulforaphane in broccoli, various components (like glucoraphanin, sulforaphane, myrosinase, etc.) and factors (temperature and moisture) involved in the metabolism pathway were analyzed. In this investigation, the combinations of exogenous pretreatment (melatonin or vitamin C) and contact ultrasound-assisted air drying were utilized to dry broccoli florets. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |