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1.
Heliyon ; 10(2): e24900, 2024 Jan 30.
Article in English | MEDLINE | ID: mdl-38312636

ABSTRACT

Herein, a new method was developed to obtain a crude extract from sword beans at a higher extraction efficiency. The crude extract formed a gel at 8 °C, which melted at 70 °C, and lyophilization of the purified gel produced a powder that could be dissolved in distilled water at a concentration of 7 % (w/w) or less. A 3 % powder solution gelled at 12 °C and melted at 60 °C. The infrared spectrum of the gel powder was consistent with that of starch. Furthermore, a 4-aminobenzoic acid ethyl ester-labeling analysis revealed that glucose was the constituent sugar in the powder, and the powder solution reacted strongly in a starch-iodine test. These observations confirmed that the gelling substance was starch. However, the melting and gelling temperatures were dissimilar to those of other starches frequently used in the food industry. Thus, our results provide valuable information for using sword bean starch as a novel food material.

2.
Heliyon ; 8(9): e10454, 2022 Sep.
Article in English | MEDLINE | ID: mdl-36060460

ABSTRACT

Tofu, a common part of the Asian diet, is soft, making it a good candidate for developing foods for people with dysphagia. Honey can coagulate soymilk proteins due to high levels of gluconic acid. In the present study, we aimed to investigate the soymilk-coagulating ability of 19 honey varieties to develop a soft sweet for people with dysphagia. We found that honey gathered from flora on Awaji Island had a higher coagulating ability than those of 18 other tested honey varieties. Based on the volume-to-weight ratio of honey, trial products were processed at honey concentrations of 20%, 25%, and 30% (w/w). The hardness, adhesiveness, and cohesiveness of products were examined according to the Consumer Affairs Agency's permissible criteria for foods for people with dysphagia. The hardness and adhesiveness of products at 25% and 30% honey concentrations were significantly higher than those at 20% honey concentration. Overall, the product evaluation was consistent with Permission Criteria II (can be swallowed after slight maceration). In terms of physical properties and product cost, the added honey concentration was determined to be 25% (w/w) for commercialization. The sweet was named "Tofun" and commercialized via collaboration with a local company as part of our community development efforts. The introduction of Tofun will encourage further innovation in the sugar confectionery industry.

3.
Heliyon ; 7(6): e07239, 2021 Jun.
Article in English | MEDLINE | ID: mdl-34189298

ABSTRACT

Tofu is produced by adding a coagulant such as MgCl2 and glucono-δ-lactone (GDL) in soymilk. However, the molecular mechanism of tofu formation by adding these coagulants has been compared between the results obtained under different conditions. In this study, the formation of a tofu-like precipitate (TLP) by adding GDL was directly compared with that formed by adding MgCl2 under the same conditions except for the coagulants. The effects of both the coagulants were almost the same on the changes in the precipitate weight, supernatant protein concentration, and urea-soluble protein concentration, indicating that a common contributing factor induces TLP formation. However, the effects of the coagulants on pH were largely different, suggesting that pH reduction is not an absolute requirement in TLP formation induced by adding MgCl2. Moreover, the findings of this study revealed that the decrease in the surface charge of soymilk proteins is a common initiation factor for TLP formation, whereas the intermolecular hydrophobic interaction is an important factor for the formation of urea-insoluble precipitates. Overall, these findings will be useful in discovering new coagulants to enhance the quality characteristics of tofu.

4.
Heliyon ; 6(4): e03673, 2020 Apr.
Article in English | MEDLINE | ID: mdl-32322706

ABSTRACT

Gluconic acid, the major organic acid in honey, is a partial hydrolysate of glucono-δ-lactone, typically used as a coagulant in preparing tofu. The present study aimed to examine the coagulation potential of five different types of honey at different concentrations, upon addition to soymilk. In some samples, aggregates formed in the upper layer at a higher honey concentration, while in others, aggregates precipitated at an intermediate honey concentration. Both phenomena were reproduced by adding different mixtures of glucono-δ-lactone and glucose, indicating that gluconic acid concentration and total sugar content of honey can trigger soymilk coagulation. Interestingly, honeys with a high concentration of gluconic acid showed a low total sugar content. Furthermore, in a trial product, the mixture of blended honey with soymilk was determined to be pasty. Our results indicate that honey can coagulate soymilk, which may provide a new and convenient method to prepare soymilk-based industrial products.

5.
Heliyon ; 5(12): e03037, 2019 Dec.
Article in English | MEDLINE | ID: mdl-31890966

ABSTRACT

Canavalin is the major storage protein in sword beans (Canavalia gladiata) and belongs to the 7S seed globulin class. Canavalin solubility can be reversibly altered via the addition of MgCl2 and CaCl2 at different concentrations; specifically, it is insoluble at lower concentrations and soluble at higher concentrations. However, the addition of NaCl does not induce the insolubilization of canavalin. In this study, it was determined that the addition of NaCl causes the nearly complete solubilization of MgCl2-precipitated canavalin in the presence of high concentrations. Moreover, using gel filtration we examined the quaternary structures of soluble canavalin in the bean extract and in the presence of high-concentration salts. Results indicated that canavalin was present in the monomer form within crude extracts with distilled water. Alternatively, we identified trimeric soluble canavalin in the presence of high concentrations of NaCl or MgCl2. Our study revealed that the quaternary structures of sword bean soluble proteins differ in crude extract compared to those in high-concentration salt solutions. The three-dimensional structure of ß-conglycinin, which is a typical 7S-seed globulin in soybean, has a trimer form in the presence of high concentrations of NaCl. However, it remains unclear whether ß-conglycinin is present as trimers in soybean seed. Our findings serve as an important reference to analyze 7S globulin characteristics.

6.
Heliyon ; 4(9): e00817, 2018 Sep.
Article in English | MEDLINE | ID: mdl-30259000

ABSTRACT

Different coagulant concentrations can induce urea-soluble precipitates (USPs) and urea-insoluble precipitates (UIPs) during tofu-like precipitate formation. In this study, MgCl2 concentration-dependent changes in USPs were quantified using a method based on urea solubility differences in order to investigate the factors affecting USP versus UIP formation. The addition of various Mg salts revealed that anions influence the solubility of proteins in both USPs and UIPs. Moreover, addition of MgCl2/NaCl mixtures, in which the Cl- concentration was held constant, demonstrated that Mg2+ was essential for UIP formation but not for USP formation and that Cl- was inconsequential for both USP and UIP formation. NaCl addition showed that the driving force for USP formation was salting-out due to the presence of cations. Overall, our data indicated that the Mg2+ concentration determined the separation of USPs and UIPs. These results will help elucidate the molecular mechanisms mediating the separation of silken tofu and regular tofu.

7.
Biosci Biotechnol Biochem ; 82(10): 1821-1824, 2018 Oct.
Article in English | MEDLINE | ID: mdl-29966493

ABSTRACT

Two variants of the sword bean (Canavalia gladiata), namely the white sword bean (WSB) and the red sword bean (RSB), are known. The MgCl2 concentration-dependent canavalin solubility showed different behavior among the extracts from distinct beans prepared by distinct pretreatments. Pretreatment and bean selection are important factors for use in food chemical and biochemical experiments.


Subject(s)
Fabaceae/metabolism , Plant Proteins/isolation & purification , Electrophoresis, Polyacrylamide Gel , Fabaceae/embryology , Plant Proteins/metabolism , Seeds , Solubility
8.
Biosci Biotechnol Biochem ; 82(1): 120-126, 2018 Jan.
Article in English | MEDLINE | ID: mdl-29191143

ABSTRACT

White sword bean (Canavalia gladiata) seeds have the potential to be utilized in the manufacturing of processed foods owing to their high protein and carbohydrate content. Our previous reports explored the use of the sword bean as a source of food materials by preparing extracts in distilled water. In the present study, we found that one such extract can be gelated by cooling. The gelling substances were extracted by boiling and simultaneously stirring a suspension containing ground beans. Few proteins were present in the gelated extract. We also examined the conditions under which gelation occurred and the gel melting temperature. The extract gelated at temperatures below 10 °C, and the resulting gel melted at those above 65 °C. This is the first report that gelling substances can be extracted from sword beans in large quantities. We expect that this gelling agent can be used for the production of processed foods.


Subject(s)
Canavalia/chemistry , Gels/chemistry , Plant Extracts/chemistry , Seeds/chemistry , Cold Temperature , Proteins/chemistry
9.
Biosci Biotechnol Biochem ; 81(4): 779-782, 2017 Apr.
Article in English | MEDLINE | ID: mdl-28100101

ABSTRACT

Espresso coffee foam, called crema, is known to be a marker of the quality of espresso coffee extraction. However, the role of foam in coffee temperature has not been quantitatively clarified. In this study, we used an automatic machine for espresso coffee extraction. We evaluated whether the foam prepared using the machine was suitable for foam analysis. After extraction, the percentage and consistency of the foam were measured using various techniques, and changes in the foam volume were tracked over time. Our extraction method, therefore, allowed consistent preparation of high-quality foam. We also quantitatively determined that the foam phase slowed cooling of the liquid phase after extraction. High-quality foam plays an important role in delaying the cooling of espresso coffee.


Subject(s)
Coffee , Food Handling , Hot Temperature , Humans
10.
Biosci Biotechnol Biochem ; 80(12): 2459-2466, 2016 Dec.
Article in English | MEDLINE | ID: mdl-27562119

ABSTRACT

Canavalin is a vicilin-class (7S) storage protein found in sword bean (Canavalia gladiata). Our previous report indicated that canavalin is precipitated by the addition of 20 mM MgCl2 to crude sword bean extract. Here, we examined the solubility changes induced by the addition of Mg2+ and Ca2+ at various concentrations. Canavalin tended to be insolubilized at relatively low concentrations of MgCl2 (< 20 mM) and solubilized at relatively high concentrations (> 20 mM). In addition, canavalin was slightly insolubilized in the presence of NaCl. Overall, the results revealed that solubility changes are reversible and depend on the concentration of divalent cations. Therefore, we suggested a reaction scheme that describes the effects of divalent cations on the solubility of canavalin, which would facilitate the study of its physiological function and the application of canavalin in the food processing industry.


Subject(s)
Cations, Divalent/pharmacology , Fabaceae/chemistry , Plant Proteins/chemistry , Dose-Response Relationship, Drug , Food Industry , Solubility/drug effects
11.
Biosci Biotechnol Biochem ; 80(8): 1623-31, 2016 Aug.
Article in English | MEDLINE | ID: mdl-27022983

ABSTRACT

Sword bean (Canavalia gladiata) seeds are a traditional food in Asian countries. In this study, we aimed to determine the optimal methods for the precipitation of sword bean proteins useful for the food development. The soaking time for sword beans was determined by comparing it with that for soybeans. Sword bean proteins were extracted from dried seeds in distilled water using novel methods. We found that most proteins could be precipitated by heating the extract at more than 90 °C. Interestingly, adding magnesium chloride to the extract at lower temperatures induced specific precipitation of a single protein with a molecular weight of approximately 48 kDa. The molecular weight and N-terminal sequence of the precipitated protein was identical to that of canavalin. These data suggested that canavalin was precipitated by the addition of magnesium chloride to the extract. Our results provide important insights into the production of processed foods from sword bean.


Subject(s)
Canavalia/chemistry , Food Technology/methods , Magnesium Chloride/chemistry , Plant Proteins/chemistry , Seeds/chemistry , Chemical Precipitation/drug effects , Hot Temperature , Humans , Kinetics , Molecular Weight , Glycine max/chemistry
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