The fluorescence fingerprint, also known as the excitation-emission matrix (EEM), is a set of fluorescence spectra acquired at consecutive excitation wavelengths to create a three-dimensional diagram. The pattern of this diagram is unique for each measured sample, and contains abundant information about the constituents making up the sample. By combining current information technologies and large amounts of data, fine distinctions are able to be made between samples that would otherwise be indistinguishable. The following applications using this technology are discussed in this paper : discrimination of the geographic origin of mangoes ; prediction of buckwheat flour ratio in commercial dried buckwheat noodles ; and detection of mycotoxins in wheat and nutmeg.
Soyasaponins : Soyasaponins are triterpene glycosides that possess an oleanane-type aglycone with 1 or 2 polysaccharide chains. Due to differences in the aglycone compounds, soyasaponins are mainly classified as group A or B soyasaponins. Soyasaponins, especially group B soyasaponins, have been reported to have several physiological functions such as antioxidative, cholesterol-lowering, antiviral, anti-inflammatory, renin-inhibiting, hepatoprotective, and antitumor effects. We found that group B soyasaponins are more readily absorbed than group A soyasaponins, which may explain why group B soyasaponins exhibit more potent effects. Vitamin K2 : Vitamin K is a cofactor required for post-translational gamma-carboxylation of vitamin K-dependent proteins, including coagulation factors, anti-coagulation factors, osteocalcin (OC) in bone, and matrix Gla proteins (MGP) in arteries. Among major vitamin K homologues in foods, only vitamin K2 as menaquinone-7 (MK-7) can activate osteocalcin, which modulates bone structure at nutritional doses. Vitamin K2 also induces collagen accumulation in bone, contributing to bone quality and strength. In addition, MK-7 activates MGP, an artery calcification inhibitor, and is reported to be associated with the prevention of cardiovascular diseases. The higher efficacy of MK-7 compared to other vitamin K homologues is due to the better absorption and longer half-life of MK-7.
In soybean, a number of biologically active, and thus beneficial, substances have been identified ; including isoflavone, lecithin, and saponin. Some of these are currently being marketed because their health promoting functions have been publicly approved. Moreover, recent evidence has accumulated suggesting that soybeans could contain other unused compounds with valuable functions as food additives. In this review, we focus on black soybean seed coat polyphenols (BSCP) and pinitol (PI). BSCP mainly consists of procyanidin, cyanidin 3-glucoside, and epicatechin, which are all well known for their antioxidant properties. Procyanidin represents a group of oligomeric compounds formed from catechin and epicatechin molecules. BSCP is characterized by its specific composition of procyanidin, and is particularly rich in smaller oligomer forms. It is thought that procyanidin oligomer size is inversely correlated to bioavailability. PI (3-O-methyl-D-chiro-inositol) is an inositol derivative that chiefly exists in legumes and pines, and is characterized by its extremely high water-solubility. PI content in soybean seed was reported to be around 0.2% dry weight, while in soybean plant, it is one of the major low-molecular weight carbohydrates ; moreover, it is very rich in soybean leaves (up to 2% of dry weight). Intriguingly, both BSCP and PI exert anti-diabetic and anti-obesity effects. However, they have been under-utilized mainly due to a lack of efficient methods for stable and effective handling. Here we discuss both plausible mechanisms that could enable the exertion of beneficial functions and recent developments in their preparation from raw materials.