The chemistry,distribution,and metabolic modifications of fruit flavonols

Fruits are considered as healthy foods because they provide a rich source of vitamins,antioxidants and other nutrients,including a range of essential bioactive flavonoid compounds.Flavonols,with diverse chemical properties and biological activities,are the most ubiquitous flavonoids that occur naturally in fruits and they are nutritionally important to animals and humans.Numerous investigations have emphasized that significant intake of dietary flavonols is associated with lower incidences of degenerative diseases.Here,we review current knowledge concerning the molecular structures,composition and distribution,regulation,and structural modification of fruit flavonols.In addition,we consider biotechnological approaches to enhance the levels of flavonols in plants or microorganism.An understanding of the factors determining production of flavonols in fruit crops will improve breeding programs and facilitate the production of fruits or bio-products with desirable contents of bioactive flavonols of benefit to humans.

Naringin,neohesperidin and their corresponding dihydrochalcones as bioactive substances:a symphony of bitter–sweet

Bitter is generally undesirable,although it is an important part of flavor.Bitter substances exhibit diverse health-promoting activities,which is in line with the famous Chinese saying‘a good medicine tastes bitter’.Naringin(NAG)and neohesperidin(NHP),two important flavanones that give bitterness to citrus fruits,show various pharmacological activities.Interestingly,their hydrogenation products,i.e.naringin dihydrochalcone(NDC)and neohesperidin dihydrochalcone(NHDC),undergo a dramatic taste shift from bitter to intensely sweet,which can be 300 and 1000 times sweeter than sucrose,respectively.Such sweeteners not only provide a sweet taste without the burden of increased calorie intake and glycemia,but also may exert multiple bioactivities.This review summarizes common dietary bitter and sweet compounds with sensory scores.Taste conversions induced by structural changes from bitter NAG and NHP to sweet NDC and NHDC are particularly discussed.In addition,the taste-sensing mechanisms,pharmacological characteristics,dietary distribution,synthesis,and food industry applications of these bitter–sweet interchangeable compounds are outlined.In conclusion,the bitter NAG and NHP are promising therapeutic candidates for management of diverse etiologically complex diseases while their corresponding dihydrochalcones NDC and NHDC are promising sweeteners,which might be a blessing for those who need to control sugar intake.

The chemistry,stability and health effects of phenolic compounds in cultivated hawthorn(Crataegus pinnatifida var.major):a review

Cultivated hawthorn(Crataegus pinnatifida var.major),the principal cultivated hawthorn species in China,is rich in phenolic compounds.These phytochemicals are considered essential bioactive ingredients in different organs of cultivated hawthorn,contributing to its health effects.However,there is lack of a comprehensive review that systematically summarizes the chemistry,health effects,and stability of phenolic substances.This review summarizes recent progress in the characterization,classification,and distribution of phenolic compounds in C.pinnatifida var.major,including procyanidins,flavonoids,phenolic acids,lignans,and others.Importantly,the stability of these compounds was found to be influenced by factors such as the hawthorn development process,postharvest storage,postharvest processing,and the gastrointestinal tract environment.Additionally,the health effects of phenolic compounds in cultivated hawthorn and their underlying mechanisms were discussed.This review provides valuable insights into the utilization of hawthorn resources and the development of the hawthorn industry.