Reference Number: 159
Six selected phenolic aglycons (caffeic and ellagic acids, kaempferol, quercetin, myricetin, and morin) in nine types of berries, and their changes as influenced by jam processing, have been evaluated using optimized HPLC with diode-array detection. The berry samples, fresh and after jam processing, were analyzed, and the total amounts of selected phenolics as aglycons were identified and determined by acid hydrolysis. Their contents in fresh and jam samples did not indicate appreciable changes; therefore, the influence of jam processing on these selected phenolics in berries was suggested to be small, and was mostly present in berries as several conjugated forms that were glycosylated, esterified, etc., in the samples. The total phenolic content of each sample was also determined by the Folin-Ciocalteu method. The three samples of each berry, namely fresh, jam, and acid hydrolysate of the berry, had similar total phenolic contents. On the other hand, the scavenging effect on the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical was measured, and acid hydrolysates showed stronger activity than that of the fresh and jam-processed samples for all of the berry types.
SIGNIFICANCE OF THIS STUDY
The current paper looked at the fluctuations of six selected phenolics and the total phenolic amounts in fresh berries and in jam as processed berries. The study showed that flavonoids and phenolic acids widely distributed as conjugated forms in berries, for the most part, retained their conjugated forms during jam processing. Fluctuation in the selected phenolic contents due to jam processing was slight and hence, it was suggested that they might be present as the conjugated forms in jam. Although levels of anthocyanins are significantly lost during the processing of berries into jam, there is still hope that some other phenolic groups are still retained during jam making. The total phenolic content between fresh and processed berries can also significantly vary based on the type of berry.
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