Color is an important characteristic of food. Over the last 15 years, more attention has been paid to natural colorants because of the rising demand for clean‐label food products. Anthocyanins, which are a group of phytochemicals responsible for the purple, blue or red hues of many plants, offer a market advantage. In addition, anthocyanin‐rich foods are associated with protection against cardiovascular disease, thrombosis, diabetes, cancer, microbial‐based disorders, neurological disorders, and vision ailments. However, the real health value of anthocyanins, whether as a natural colorant or a functional ingredient, is dependent on the ultimate bioaccessibility and bioavailability in the human body. Many animal and human clinical studies revealed that, after intake of anthocyanin‐rich foods or anthocyanin extracts, only trace amounts (< 1% of ingested content) of anthocyanins or their predicted metabolites were detected in plasma after a standard blood draw, which was indicative of low bioavailability of anthocyanins. Protein binding to anthocyanins is a strategy that has recently been reported to enhance the ultimate bioactivity, bioaccessibility, and bioavailability of anthocyanins as compared to anthocyanins delivered without a protein carrier. Therefore, in this review, we address anthocyanin properties in food processing and digestion, anthocyanin‐protein complexes used in food matrices, and changes in the bioaccessibility and bioavailability of anthocyanins when bound into anthocyanin‐protein complexes in foods. Finally, we summarize the challenges and prospects of this delivery system for anthocyanin pigments.

Berry fruits, such as strawberries and blueberries, are rich sources of anthocyanins. Several studies have been made on the impact of non-thermal treatments on safety, shelf-life and nutritional characteristics of such products, but the effects of these processes on anthocyanin stability during digestion in the gastrointestinal tract are still not completely clear. The aim of this study was to assess the recovery of anthocyanins after simulated gastrointestinal digestion of (1) strawberry samples, pre-treated with pulsed electric field (PEF) at 100 or 200 V·cm⁻¹, prior to osmotic dehydration (OD), and (2) blueberry samples coated with chitosan and procyanidin. After digestion, a significantly higher content of cyanidin-3-O-glucoside and malvidin-3-O-glucoside was quantified by LC-MS/MS in processed strawberry and blueberry samples, compared with the controls. The highest recovery of cyanidin-3-O-glucoside was detected in digested strawberry samples osmotically dehydrated with trehalose. The recovery of malvidin-3-O-glucoside was highest in digested blueberries coated with chitosan and stored for 14 days, compared with untreated samples or samples coated with chitosan and procyanidin. Our study shows the potential of mild PEF treatments combined with OD, or the use of edible coating, to obtain shelf-stable products without substantially affecting the composition or the stability of anthocyanins during digestion in the upper gastrointestinal tract.

Bilberries are a rich natural source of phenolic compounds, especially anthocyanins. The press cake obtained during the processing of bilberry juice is a potential source of phytochemicals. The objective of this study was to evaluate different drying techniques and the fractionation of bilberry press cake powder toward obtaining phenolic‐rich ingredients for incorporation into value‐added food products. The derived powders were dispersed in water and dairy cream, to investigate the effects of drying and fractionation on the dispersibility and solubility of phenolic compounds. The drying techniques, hot air drying and microwave drying, applied on bilberry press cake reduced the content of total phenolics and anthocyanins. The degradation was, however, consistently small and similar for both techniques. The major anthocyanins detected in the samples were stable during drying and fractionation treatments. Fractionation of the press cake powder affected the total apparent phenolic content and composition of the different fractions. The highest phenolic content (55.33 ± 0.06 mg g⁻¹ DW) and highest anthocyanin content (28.15 ± 0.47 mg g⁻¹ DW) were found in the fractions with the smallest particle size (<500 μm), with delphinidin‐3‐O‐galactoside being the most abundant anthocyanin. Dispersibility of all dried powder samples was higher in dairy cream than water, and the highest level of anthocyanins was measured in samples from the powder with the smallest particle size (<500 μm), dispersed in cream. The application of drying, milling and fractionation was found to be a promising approach to transform bilberry press cake into stable and deliverable ingredients that can be used for fortification of food products with high levels of phenolic compounds.

Berry powders are popular as ingredients in a range of food products, where they naturally provide flavor, color, texture, polyphenols, fiber, and other nutrients. The choices regarding processing techniques and conditions influence the quality attributes of berry powders. The aim of this study was to study the effects on bilberry powder functionalities of applying different preprocessing techniques (purée mixing and juice pressing vs. untreated whole berries) prior to hot air drying and milling. Drying of press cake reduced the drying time by 72% and increased the total apparent phenolic content of the final powder by 44%, as compared to the powder of dried whole berries. The press cake powder showed an easier flowing behavior than the powders from whole berries and puréed berries. Dispersibility (in water and dairy cream) was 60% higher for powders from whole berries and puréed berries, as compared to press cake. The total phenolic content of the dispersed powders was highest for whole berries and puréed berries. Bilberry powder functionality can be modulated through the selection of an appropriate preprocessing technique before drying and milling. This tailors the powder properties into food ingredients ready for different applications, without the need for additives.

Cocoa beans (Theobroma cacao L.) can be used for craft chocolate production, which arouses consumer interest due to their perceived better quality. This study aimed to evaluate the chemical profile of 80% artisanal chocolate samples produced with cocoa beans subjected to different maturation conditions. In the first maturation process, beans were matured under no-oxygen conditions, and in the second, the toasted beans were matured in oak barrels. The volatile compounds of the chocolate samples were extracted by the solid-phase microextraction method in headspace mode and analyzed by gas chromatography/mass spectrometer. The non-volatile compounds were extracted with methanol and analyzed through paper spray mass spectrometry. Overall, 35 volatile compounds belonging to different chemical classes (acids, alcohols, aldehydes, ketones, esters, and pyrazines) were identified, such as propanoic acid and butane-2,3-diol. In addition, 37 non-volatile compounds, such as procyanidin A pentoside and soyasaponin B, were listed. Tannins, flavonoids, and phenylpropanoids were the main chemical classes observed, varying between the two samples analyzed. Therefore, it was possible to verify that maturation conditions affected the metabolomic profile of the 80% artisanal chocolate samples, being able to influence the sensory characteristics and bioactive compounds profile. Given these results, the sensory evaluation of these chocolates is suggested as the next step.

Many studies suggest anthocyanins may prevent the development of several diseases. However, anthocyanin bioactivity against cellular stress is not fully understood. This study aimed to evaluate the protective effect of berry anthocyanins on stressed cells using Saccharomyces cerevisiae. The impact of in vitro gastrointestinal digestion on anthocyanin profiles was also assessed. Bilberry and blackcurrant had higher anthocyanin levels than raspberry and strawberry, but digestion reduced the detected anthocyanins by approximately 90%. Yeast cells with and without digested or nondigested anthocyanin extracts were exposed to H₂O₂ and examined for survival. In the presence of anthocyanins, particularly from digested strawberry, a significant increase in cell survival was observed, suggesting that the type and levels of anthocyanins are important factors, but they also need to undergo gastrointestinal (GI) structural modifications to induce cell defence. Results also showed that cells need to be exposed to anthocyanins before the stress was applied, suggesting induction of a cellular defence system by anthocyanins or their derivatives rather than by a direct antioxidative effect on H₂O₂. Overall, data showed that exposure of severely stressed yeast cells to digested berry extracts improved cell survival. The findings also showed the importance of considering gastrointestinal digestion when evaluating anthocyanins’ biological activity.