It has been almost 10 years since the beginning of availability of agricultural products developed through the use of recombinant DNA technologies. Compared to a decade ago, the public uproar over the issue seems to have settled, but surveys regarding food safety show that “genetically modified foods” are one of the top 5 constant concerns. (Essentially, the expression, “genetically modified food” is not scientifically accurate, but because of its popularity, I’ll use the term here.)
Ordinarily, new technological advances and developments are easy targets for societal controversy (especially through the mass media), and the issue of genetically modified agricultural products is a typical example. It should be noted however, that much of this uproar became possible because scares from other foods, including BSE, occurred at the same time. Therefore, I consider this hubbub to be an issue waiting to happen.
Internationally, people have been debating the risk assessment of DNA technology since its origin. An internationally sufficient risk assessment system regarding the usage of this technology has developed, and people and organizations involved in food safety take more precautions regarding this issue than any other scientific concern.
The duration between determining how to use this technology to create commercial agricultural products was probably long enough for agricultural producers and advanced nations such as the U.S. and Canada, but too short for the countries accepting them. I can see that the issue was easily affected by differences in the technological environments between leading countries and others, and differences of recognition in regards to safety and the handling of intellectual property, due to this being state-of-the-art technology at that time. On the other hand, we can say it was an opportunity for our entire society to think about these types of issues, including how to assess public opinion when using new scientific technologies on commercial goods around us, how to try forming agreements, and the scale of permissible technological risks.
Needless to say, we must have guidelines to help prevent social uproar that can be caused by introducing new technologies into food development before it happens. But that is not easy, since each consumer has a different awareness. Therefore, all stakeholders in the fields of research and development, government administration, the media, physical distribution and retail and consumption should not forget the important issues that arose regarding genetically modified foods. Therefore, I believe we all need to try developing a social system in which these stakeholders won’t forget matters of such importance.

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Since 1970, a number of new amylases and related enzymes such as hydrolases and transferases have been discovered. Using these new enzymes, various starch-related, sucrose-related and lactose-related oligosaccharides have been produced on an industrial scale. In this special issue, we review recent topics on the functional oligosaccharides.

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Human ingest two types of carbohydrate, one is digested and the other is not digested by the small intestine enzymes. Digestible carbohydrates, such as starch, sucrose, and lactose, are decomposed by gastrointestinal enzymes to monosaccharides, are spontaneously absorbed by a transporter in the small intestine, and supply energy to the host. On the other hand, non-digestible and/or non-absorbable carbohydrates, such as oligosaccharides, sugar alcohols, and dietary fibers, escape digestion in the small intestine, and reach the large intestine. Intestinal microbes metabolize these carbohydrates to short chain fatty acids and gases by fermentation. Acetate, propionate, and n-butyrate are the end products by fermentation, and they also supply energy to the host. Furthermore, non-digestible and/or non-absorbable carbohydrates are candidates for prebiotic agents.

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POs-Ca (Phosphoryl Oligosaccharides of Calcium) is a novel food material that is a calcium source manufactured from potato starch. As to the bioavailability of POs-Ca, an in vivo oral administration experiment with rats showed that the digestibility of POs-Ca was equivalent to that of maltooligosaccharides and that the plasma calcium concentration showed a slight but significant increase concurrent with increase of plasma glucose. As to the calcium absorbability of POs-Ca, in situ experiments using rat ligated jejunum loops showed that the intestinal calcium absorption rate of POs-Ca was comparable with that of the soluble calcium compounds, but was significantly higher than that of insoluble calcium groups. The total absorption rate of a 1:1 mixture of the calcium from POs-Ca and whey mineral complex (WMC) was significantly higher than that of WMC alone, suggesting that POs-Ca would be a useful soluble calcium source with relatively high absorption in the intestinal tract. POs-Ca was not fermented by mutans streptococci in vitro. As to the remineralization effect of POs-Ca on early enamel lesions, an intraoral study using three types of chewing gum was examined with double-blind and cross-over design. Both the lesion depth (ld) and the mineral loss value (⊿Z) of the enamel lesion in the group of sugar-free chewing gum with POs-Ca were significantly lower than those in the other two groups (sugar gum and sugar-free gum without POs-Ca). Thus, it is considered that the habitual use of sugar-free chewing gum with POs-Ca “POsCAM” will be beneficial to not only caries prevention but also enhancement of remineralization of teeth.

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Research on the production of oligosaccharides for foods was started around 1970-1975 in Japan, and several oligosaccharides such as starch-related, sucrose-related, and lactose-related oligosaccharides and other oligosaccharides derived from several polysaccharides as the raw materials have been developed from the early 1980s to the late 1990s. Recent developments in industrial enzyme-utilization technology have made possible a series of new oligosaccharides such as β-1,6-linked gentiooligosaccharides, α-1,1-linked trehalose, α-1,3-linked nigerooligosaccharides, branched-cyclodextrins, maltosyltrehalose, cyclic difructose and cyclic tetrasaccharide. The development of novel and highly functional oligosaccharides with physiological properties is now continuing and the market is expanding gradually.
Nigerose is a disaccharide of α-1,3-linked d-glucose, found in beer, honey and other traditional Japanese foods such as sake and sweet sake used as seasonings. Nigerooligosaccharides, a mixture of nigerose, nigerosylglucose and nigerosylmaltose, have been produced from maltose by the transfer reaction of Acremonium sp. origin α-glucosidase on an industrial scale. Nigerooligosaccharides-containing syrup is mildly sweet, and has begun to be used for various kinds of foods and beverages as a taste-improving and color-stabilizing saccharide. Furthermore, it has been revealed that nigerooligosaccharides have immunopotentiating activity in vitro and in vivo studies, and also the daily intake of nigerooligosaccharides-containing foodstuffs improves the health-related quality of life (QOL) in the elderly. In this chapter, the production method, novel functional properties and applications of nigerooligosaccharides developed as a starch-related oligosaccharide will be described.

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Cyclic nigerosyl-(1→6)-nigerose (CNN), cyclo-{→6}-α-d-Glcp-(1→3)-α-d-Glcp-(1→6)-α-d-Glcp-(1→3)-α-d-Glcp-(1→), has a unique structure consisting of four glucose residues connected by alternate α-(1→3)- and α-(1→6)-linkages. We succeeded in mass-production of CNN from starch by using a novel enzymatic system. In this review, we describe the current study of CNN. First, the CNN-synthesizing mechanism from starch is described. Second, we describe the physicochemical properties of CNN pentahydrate crystals. Finally, the physiological functions of CNN are described.

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Oligosaccharides with α-d-galactosidic linkages, especially each positional isomer of α-galactobiose (α-Gal2), participate in such biological process as immunity and pathogen-to-cell adhesion on the basis of molecular mechanisms for ligand-receptor interaction. α-Linked galactooligosaccharide (α-GOS) containing positional isomers of α-Gal2 produced from galactose by the reverse reaction of α-galactosidase, is a potential food to be used in the prevention of infections by pathogens, neutralization of toxins, and regulation of the immune system.
α-GOS was produced from galactose (prepared from lactose hydrolyzate) by the reverse reaction of α-galactosidase from Aspergillus niger APC-9319. α -GOS contained 58% disaccharide, 28% trisaccharide, and 14% oligosaccharides larger than trisaccharide. The disaccharide in α-GOS consisted largely of α-1,6-galactobiose.
α-GOS was stable at neutral and acidic pHs, and high temperatures. The sweetness of α-GOS was 25% of that of sucrose. The taste of α-GOS was mild and mellow. α-GOS reduced acid taste, bitterness, astringency, and harsh taste without spoiling the original taste in various fruit juices, and emphasized the original flavor of food materials in various cooking foods. α-GOS was not hydrolyzed in an in vitro digestion method. In oral tolerance tests of α-GOS, the blood glucose level did not change at all. α-GOS had a strong selective growth activity for Bifidobacterium sp. and Clostridium butyricum. An α-GOS intake in rats made the contents of lactate and n-butyrate in the cecum higher, and pH in the cecum lower than for a control intake. In young female students who defecated 3 to 5 times /week, the investigation of α -GOS (3 g) increased the defecation frequency and fecal volume, and improved the condition of feces by promoting the proliferation of Bifidobacterium sp. The maximum non-effective dose of α-GOS was estimated at 0.25 g/kg body weight for males and 0.33 g/kg body weight for females. The viable count of Candida albicans in the cecum and colon of mouse was decreased by an α-GOS intake more than a raffinose intake. Dietary α-GOS ameliorated allergic airway eosinophilia at least partly via post-absorptive mechanisms in Brown Norway rats. Therapeutic oral treatment with α-GOS had a potent inhibitory effect on adjuvant arthritis in Wister rats and type II collagen-induced arthritis in DBA/1J mice.

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Lactobionic acid (LacA) is an aldonic acid derived by the oxidation of lactose (Lac). This article covers the usefulness and biocatalytic production of LacA. Lac, a by-product in the dairy industry, generally undergoes enzymatic oxidation to produce lactobiono-δ-Lactone, which is spontaneously hydrolyzed to LacA in aqueous solutions. LacA is useful as a healthy oligosaccharide that promotes the intestinal adsorption of minerals and stimulates the growth of Bifidobacteria. It is also used in practice as a gelling agent for foods, a moisturizing agent for cosmetics, and a component of a preservative solution for transplanting organs. Because of these potential and practical uses, we investigated the microbial and enzymatic oxidation of Lac. As a result of screening of microorganisms, we selected a Burkholderia cepacia strain that possessed an extremely high Lac-oxidizing activity in its membrane-bound fraction and a fungal strain of Paraconiothyrium sp. that produced an extracellular oxidase. The bacterium converted Lac to LacA efficiently in fermentation. The productivity was improved by the selection of a mutant strain that acquired a tolerance to high Lac concentrations and by performing fed-batch culture of the mutant. Repeated batch reactions of the washed cells also improved the efficient accumulation of calcium lactobionate. The fungal enzyme oxidized various monosaccharides and oligosaccharides such as cellobiose and maltose in addition to Lac, using O₂ as a preferable electron acceptor. The enzyme was also suitable for the conversion of Lac to lactobionate.

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Mook is one of the typical dishes in the Korean peninsula. The ancients in this area devised the mook from wild acorn. The manufacturing process of acorn mook is as follows.
Collection of acorns → Drying → Grinding → Sieving → Removing harshness → Collection of starch → Boiling(gelatinization of starch) → Cooling(coagulation of starch) → Forming
The acorn mook has been developed into the mooks from mung beans and buckwheat crops. There are three kinds of mooks, acorn mook, mung bean mook and buckwheat mook in Korea. The mooks are not only a side dish in daily food, but courtesy and offering food in annual events. Therefore, Korea is the center concerning the culture and science of acorns in the world.

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