Effects of industrial and home-made spread processing on bilberry phenolics

Stability of polyphenols in food processing

In recent years, polyphenols have attracted considerable attention due to their diverse potential health-beneficial effects on humans. Polyphenols are widely distributed in natural plants, and therefore play an important role in human food. Thermal processing, irradiation, fermentation, high pressure, microwave, and drying are several popular food processing methods. However, polyphenols are instable in food processing, which easily degrade and react with other components because of their polyhydroxy characteristic. Traditional and advanced technologies have been used to characterize the stability of polyphenols. The main influence factors of stability of polyphenols such as pH, temperature, light, oxygen, enzymes, metal ions, as well as macromolecules, are summarized. Besides, thermal processing greatly promoted the degradation of polyphenols. Thermal degradation mechanisms and products of some polyphenols, such as quercetin and rutin, have been intensively demonstrated. Nevertheless, the structural changes of polyphenols caused by food processing, may lead to different bioactivities from the obtained results based on unprocessed polyphenols. Therefore, to maximize the beneficial effects of polyphenols ingested by human from processed food, the stability of polyphenols in food processing must be thoroughly investigated to assess their real bioactivities. In addition, some available technologies for improving the stability of polyphenols in food processing have been proposed.

Updated insights into anthocyanin stability behavior from bases to cases: Why and why not anthocyanins lose during food processing

Anthocyanins have received considerable attention for the development of food products with attractive colors and potential health benefits. However, anthocyanin applications have been hindered by stability issues, especially in the context of complex food matrices and diverse processing methods. From the natural microenvironment of plants to complex processed food matrices and formulations, there may happen comprehensive changes to anthocyanins, leading to unpredictable stability behavior under various processing conditions. In particular, anthocyanin hydration, degradation, and oxidation during thermal operations in the presence of oxygen represent major challenges. First, this review aims to summarize our current understanding of key anthocyanin stability issues focusing on the chemical properties and their consequences in complex food systems. The subsequent efforts to examine plenty of cases attempt to unravel a universal pattern and provide thorough guidance for future food practice regarding anthocyanins. Additionally, we put forward a model with highlights on the role of the balance between anthocyanin release and degradation in stability evaluations. Our goal is to engender updated insights into anthocyanin stability behavior under food processing conditions and provide a robust foundation for the development of anthocyanin stabilization strategies, expecting to promote more and deeper progress in this field.

Are Processed Bilberry Products a Good Source of Phenolics?

Bilberries are processed into different food products and beverages. Therefore, we studied how various bilberry items (puree, infusion, liqueur, and fresh and pasteurized juices) differ in secondary metabolites as compared to the fresh fruit. For this purpose, we identified phenolics with a liquid chromatography-mass spectrophotometry (LC-MS) system and compared phenolic profiles and phenolic contents in various bilberry products prepared from the same raw material. Our results show that processing significantly affected the biochemical pattern and levels of phenolics. Total analyzed phenolics decreased with processing, mostly due to anthocyanins, which had the highest share in phenolic profile of all bilberry-based products. The highest differences among products in flavanol (63.7-fold), followed by flavonol contents (26.3-fold). Fresh fruits had the highest content of total anthocyanins (5,190 mg/100 g dry weight [DW]), followed by puree (2,719 mg/100 g DW), infusion (2,469 mg/100 g DW), and liqueur (1,830 mg/100 g DW), whereas fresh and pasteurized juices had the lowest content of total anthocyanins (921 and 1,099 mg/100 g DW).

PRACTICAL APPLICATION

Although we confirmed the common belief among consumers that the consumption of fresh berries is more beneficial than consuming processed products, this study showed that various bilberry-derived products can also be valuable source of phenolic compounds all year round.

Intake of bilberries (Vaccinium myrtillus L.) reduced risk factors for cardiovascular disease by inducing favorable changes in lipoprotein profiles

Cardiovascular diseases (CVDs) are the leading causes of death, and lifestyle modification, including dietary changes, is recommended to improve this condition. In this study, regular consumption of bilberries was hypothesized to have beneficial effects on CVD risk reduction, by changes in human health indicators such as decreasing low-density lipoprotein cholesterol (LDL-C) and triglycerides (TGs) and increasing high-density lipoprotein cholesterol (HDL-C). The research involved women (n=25) and men (n=11) who consumed 150 g of frozen stored bilberries 3 times a week for 6 weeks. Anthropometric parameters, blood pressure, lipid profile, glucose, liver enzymes, creatinine, albumin, magnesium, and antiradical activity were measured. Except for the body mass index of women (P=.019), no significant changes were found for anthropometric indicators. The consumption of bilberries led to a decrease in the following parameters: total cholesterol (P=.017), LDL-C (P=.0347), TG (P=.001), glucose (P=.005), albumin (P=.001), γ-glutamyltransferase (P=.046), and a positive increase in HDL-C (P=.044). In men, additionally, favorable changes were observed in total cholesterol (P=.004), glucose (P=.015), albumin (P=.028), aspartate aminotransferase (P=.012), γ-glutamyltransferase (P=.013), and HDL-C (P=.009; in this group, LDL-C increased [P=.007]). Changes in other parameters were not significant, for both women and men. Thus, the regular intake of bilberries can be important to reduce CVDs risk, by decreasing LDL-C/TG and increasing HDL-C.

Influence of storage conditions in the evolution of phytochemicals in nutraceutical products applying high resolution mass spectrometry

An adequate knowledge about possible transformation of bioactive compounds in nutraceutical products during long storage is important in order to know potential modifications of this type of compounds. In this study, one year monitoring was performed in different types of nutraceutical products based on natural extracts (green tea, soy, royal jelly and grapes) observing the appearance of new bioactive compounds, which were not detected at the initial conditions, as well as the decrease of some of the detected compounds. To determine these transformation products, an analytical procedure based on high resolution mass spectrometry (Exactive-Orbitrap analyzer) was applied. It was noted that transformation products were detected after 3 months of storage in green tea and soy products, while 6 months were necessary to observe transformation products in royal jelly.