Two diacylated malvidin glycosides from Petunia hybrida flowers

Enzymatic Acylation of Black Rice Anthocyanins and Evaluation of Antioxidant Capacity and Stability of Their Derivatives

In this study, the structure of the anthocyanin fractions isolated from black rice (Oryza sativa L.) was modified by the enzyme catalysis method using caffeic acid as an acyl donor. At the same time, the effects of the acylation on the lipophilicity, antioxidant activity, and stability of black rice anthocyanins were comprehensively evaluated. The structural analyses of acylated derivatives based on ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, ultra-high-performance liquid chromatography-high-resolution mass spectrometry, and thermogravimetric analysis revealed that caffeic acid was efficiently grafted onto the anthocyanins of black rice through an acylated reaction, while the acylation binding site was on glucoside. When the mass ratios of anthocyanins to caffeic acid were 1:1, the A319/AVis-max value of acylated anthocyanins reached 6.37. Meanwhile, the lipophilicity of acylated derivatives was enhanced. The antioxidant capacity (DPPH and FRAP) and stability (thermal, pH, and light stability) were significantly increased. Overall, the study results provide deeper insights into controlling anthocyanin homeostasis in food processing, broadening the application of colored grain products.

Ferulic Acid and Naturally Occurring Compounds Bearing a Feruloyl Moiety: A Review on Their Structures, Occurrence, and Potential Health Benefits

The ubiquitous compound 4-hydroxy-3-methoxycinnamic acid, also known as ferulic acid (FA), constitutes a bioactive ingredient of many foods that may offer beneficial effects against disorders related to oxidative stress, including cancer, diabetes, and neurodegenerative diseases. This review discusses the antioxidant properties of FA, establishing relationships to several biological activities already described for this natural product. Next, 387 naturally occurring compounds, all isolated from plants and published between 1990 and 2015, the structures of which bear 1 or more feruloyl moieties, are covered in this review along with their structural formulas, botanical sources, and bioactivities. The compounds' distribution, structural patterns, bioactivities, and perspectives on food research are also succinctly discussed.

Why are grape/fresh wine anthocyanins so simple and why is it that red wine color lasts so long?

Vitis vinifera red berries are characterized by anthocyanins whose chemical structures are among the simplest encountered in higher plants. On the contrary, many plants, including orchids, petunias, red cabbage, elderberries, potatoes for instance, have developed very complicated anthocyanins featuring side-chains at the available positions of the aglycone skeleton. Such pigments were shown to possess bio-physico-chemical properties not to be seen with the grape common anthocyanins. Among beverages (water, tea, beer, wine, coffee, juices, milk), red wine is the only one whose organoleptic properties improve with time and this is called ageing. The grape/fresh red wine pigments, after a few months, disappear from the wine giving birth to new pigments resulting from the wine spontaneous chemistry allowing it to remain red for many years. What are the wine pigments and why are they so stable is the purpose of this mini-review. The structural simplicity of grape anthocyanins and the long lasting colour of red wine is another French paradox; we call it French paradox II.