Olives and olive oil have established, through centuries, strong bonds with the prosperity and well being of the Mediterranean people. Numerous studies have featured them as main antioxidant sources, based on their phenolic profile, which includes phenolic acids and alcohols, polyphenols, lignans, secoiridoids, oleacein and oleocanthal. Several factors, such as cultivar, fruit maturation, processing methods, storage conditions etc. affect the presence of these significant constituents in the products. Re-use of olive mill waste water has been studied to enrich the phenolic profile of the final product. Olive oil is considered a functional food with extensive use in the food industry. The biological effects of olives and virgin olive oil components include protection against cardiovascular diseases, anti-inflammation action, neuro and endothelial protection etc. Research studies, in vitro and in vivo, in humans and in animals have been performed to better understand the metabolism and bioactivity of olives and olive oil phenolics. Olives and olive oil antioxidants are not only absorbed by the body, but can also attach to the lining of the digestive tract, contributing to the health impact afforded by these products. Laboratory methods and techniques used so far for the qualitative and quantitative identification of these compounds are cited.

Postharvest storage of many freshly picked berries affects polyphenol and sugar content. However, little is known about the impact of refrigerated and frozen storage on aronia berry composition. Therefore, the objective of this study was to characterize how storage at 4 ± 2 °C and − 20 ± 2 °C, and temperature cycles affect aronia berry polyphenols, total solid content, pH, titratable acidity, polyphenol oxidase (PPO) activity, sugar content, acid content, color, and cell structure. Refrigerated storage reduced proanthocyanidins (21%), anthocyanins (36%), and total phenols (21%) after 12 weeks. Frozen storage increased polyphenols in the first 6 mo. of frozen storage but then decreased polyphenols at mo. 8 to levels similar to initial values. Frozen temperature cycling reduced anthocyanins 18% but did not affect total phenols or proanthocyanidins. Scanning electron microscopy analysis indicated temperature cycling induced cell damage, shrinking, and fusion. This disruption led to the release of anthocyanins inside the berry tissue. PPO activity did not significantly correlate with the decrease in polyphenol content during storage. °Brix did not significantly change during refrigeration and frozen storage but did during the 12th temperature cycle. Aronia berries’ pH and titratable acidity were affected more by refrigeration than frozen and temperature storage. The pH increased by 4% during refrigeration, and titratable acidity decreased by 17% at 12 weeks. In conclusion, refrigerated storage results in a modest reduction of aronia berry polyphenols, but absolute extractable polyphenols are stable for up to 8 months of frozen storage. Graphical abstract

Aronia berries (Aronia melanocarpa and Aronia mitschurinii) are underutilized functional food, rich in bioactives. Aronia berries have abundant levels of anthocyanins, proanthocyanidins, flavonols, and phenolic acids that may reduce the risk of non-communicable diseases such as diabetes, metabolic syndrome, and neurological disease. Aronia polyphenols are bioavailable, and the majority are transformed into low molecular-weight phenolics. The impact of biotransformation on aronia polyphenols health effects is not fully understood. The objective of this review is to analyze aronia berry composition, including polyphenols nutrients. Additionally, this review summarizes recent preclinical and clinical studies on the polyphenol bioavailability and health benefits upon aronia berry consumption to better understand its potential as a functional food.

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