[Objective]

　In Japan, the declining food self-sufficiency rate and protein crisis have led to exploring insect eating as a solution. This study examined a new processing method for edible crickets.

[Method]

　Commercially available cricket powder was used, with samples prepared by adding dolomite or persimmon powder, followed by high-pressure enzymatic treatment adding soy sauce koji. Color, viable cell count, allergenicity, GC-MS, and sensory tests were conducted. No color changes were observed. Viable cell counts indicated the product is safe for consumption. Allergenicity tests showed a negative reaction after high-pressure treatment. Sensory tests found no significant differences in smell and taste between samples with and without additives, similar to soy sauce.

[Results and Discussion]

　The results suggest that extracting and processing crickets with additives and seasonings can reduce the cricket-specific odor and improve taste and functionality, enabling upcycling into value-added products. This research was supported by JSPS KAKENHI grant 24K05578.

Purpose: Improving gut health and preventing non-communicable diseases (NCDs) are globally recognized challenges. Resistant protein, an indigestible fraction derived from soybean protein, has been proposed to possess these preventive effects. This study aims to develop and evaluate the properties of soft capsules using soybean resistant protein as a film material.

Methods: The effects of additives, processing methods and conditions on film formation were investigated with soy protein isolate powder. The thermal properties, tensile strength, and enzyme resistance of the obtained films were evaluated. A manufacturing method for edible soft capsules using soybean resistant protein films was developed, and the dissolution and content protection properties of the resulting capsules were evaluated in simulated gastric fluid (SGF) or fed-state simulated intestinal fluid (FeSSIF) containing digestive enzymes.

Results: A 1:1 mixture of polyol and soy protein isolate was heated and pressed using an extruder or a hot press machine. The resulting film, which was pale yellow with partial transparency, exhibited thermoplastic properties and a tensile strength of 3.28 ± 0.34 N/mm2. Thermal analysis revealed no significant differences in glass transition temperature or dynamic viscoelasticity before and after film formation. The molecular weight distribution of peptide fragments in the film was the same before and after filming, indicating a non-molecular cross-linking mechanism of film formation. Soft capsules using this film didn’t disintegrate in water, pH 1.2, or pH 6.8 buffer, but liquid penetration into the capsules was observed in SGF or FeSSIF containing digestive enzymes.

Purpose: This study aimed to report the release of various volatiles from O/W emulsion prepared with polygalacturonase (PG) treated apple pectin. Present study also examined the effectiveness of using partition coefficient to predict aroma release behaviour (release rate and release concentration) under varies of viscosities, aiming to have a further understanding of dynamic aroma release in complex food emulsion. Method: Apple pectin (0.3-1.2% w/v) were dissolved in distilled water. ML-750 (1% w/v) was added into the pectin solution as an emulsifier. Flavoured canola oil (10% vol) was then added into the pectin solutions, and passed through a membrane emulsification apparatus to obtain the monodispersed O/W emulsion. The viscosities of obtained samples were measured and the headspace aroma from the flavoured emulsion was quantified by GC-FID. The aroma of flavoured emulsion was allowed to release for 15-300 seconds before collection.Result: In this study, we found increasing the pectin content would decline both the initial release rate and total release concentration in the headspace. Furthermore, enzymatic treatment by polygalacturonase (PG) significantly disrupted the pectin backbone structure, consequently modified its molecular weight and rheological properties. O/W emulsion prepared by PG treated pectin having a significantly lower viscosity, consequently promote the release of hydrophobic aroma. Moreover, this study also reports that logPwa and logPow values can effectively estimate both release rate and concentration of hydrophobic aroma from O/W emulsion and these correlation coefficients vary over emulsion systems.

[Purposes]

We used pressurized CO₂ (PCO₂) as an environmentally friendly method for pectin extraction because it does not require acidic or basic solvents. Pectin extracted by PCO₂ (PCO₂-pectin) from grapefruit has unique properties, including a larger molecular weight (MW), a higher degree of esterification (DE), and a more branched structure than pectin extracted by the conventional method with HCl (CM-pectin). However, the PCO₂ method provided a low pectin yield (7.4%), which was insufficient for commercial purposes (1). Therefore, this study aimed to (i) employ PCO₂ and green chemicals to improve pectin extraction, and (ii) evaluate the physicochemical characteristics of the extracted pectin.

[Methods]

One gram of grapefruit residue powder was suspended in 30 mL of deionized water, as well as 30 mM sodium citrate, sodium oxalate, sodium acetate, and sodium phosphate solutions. The extraction process was conducted under PCO₂ at 2.5 MPa, at 90°C for 180 min. Pectin in the solution was precipitated, purified using ethanol, and dried. The yield and physicochemical structure of the dried pectin were determined. Response surface methodology (RMS) analysis was used to determine the optimal extraction conditions.

[Results]

PCO₂ produced the highest pectin yields of 41% and 46% (w/w) with high DE when sodium oxalate and sodium phosphate were utilized, respectively. PCO₂ with sodium oxalate retained a pectin structure comparable to that of water extraction, whereas PCO₂ with sodium phosphate exhibited higher branching and MW. The optimal conditions for maximum yield were determined to be 90°C for 180 min with 30 mM sodium oxalate.

We aimed to clarify the effects of adding white soy sauce in bread making. Roll breads were prepared by adding white soy sauce heated to inactivate the enzyme, unheated white soy sauce, or a commercially available amylase preparation. The addition of unheated white soy sauce yielded dough softening effects comparable to those achieved with amylase preparations. Both heated and unheated white soy sauce resulted in superior browning effects on bread compared to the amylase preparation. Additionally, they exhibited similar effects in terms of increased volume and improved and maintained softness of bread. It was suggested that cheese-like and savory aromas were imparted, and the umami, cheese-like flavor, and taste intensity were enhanced. These characteristics were more pronounced when unheated white soy sauce was added than heated white soy sauce.

[Objective] Proteins have surfactant activity and are used as foaming agents in the food industry. Structural changes of proteins occur at the air-water interface, and the structure of proteins at the interface is closely related to the foaming properties. In this study, to elucidate the protein structure at the foam surface, we established a novel structural analysis method using hydrogen/deuterium exchange mass spectrometry (HDX-MS) and analyzed human serum albumin (HSA) and ovalbumin (OVA).

[Methods] The hydrogen/deuterium (HD) exchange in the foam and solution states were monitored by mass spectrometry and compared between the two states. The structural change of the proteins and the adsorption sites to the interface were identified based on the difference in the HD exchange rate.

[Results] For HSA, the N-terminus and a loop (E492-T506) were identified as adsorption sites, and structural changes were widely observed throughout the structure. Analysis by circular dichroism spectroscopy and HDX-MS after defoaming suggested that the structural changes at the air-water interface were reversible (Enomoto et al. J Agric Food Chem. 2024). For OVA, three peptides (Y107-Y118, I157-A172, and F189-M212) were considered as adsorption sites. Since the adsorption sites of both HSA and OVA contained hydrophobic amino acids and were flexible sites such as loops, both structural flexibility and hydrophobicity could be important factors for the adsorption to the air-liquid interface.

“Purpose,” In our previous report, we evaluated the rheo-impedance behavior of a gelatin solution during the gelation process. No clear change was observed in the viscoelastic behavior from the sol to the sol-gel transition. However, the internal resistance of the system calculated from the impedance |Z| increased exponentially. We considered that the increase in the internal resistance corresponded to the increase in the molecular weight of the collagen molecules due to the progress of the cross-linking. In this study, the effect of the cooling rate on the rheo-impedance behavior of the gelatin was investigated.“Methods,” A 2.5wt% Gelatin B (alkali-treated, Nitta gelatin) solution was used, and was heated to 65°C and stirred. The solution was cooled to 5°C at a rate of 1°C to 4°C/min and then maintained at 5°C. For the rheo-impedance measurement, the rheometer (MCR302e, Anton Paar) and the impedance analyzer (IM-3536, Hioki) connected with BNC-SMB conversion cables.“Results,” The elastic moduli increased rapidly and reached constant as the gelatin solution was cooled. The apparent sol-gel transition point shifted to the shorter time side as the cooling rate increased. The elastic moduli, which reached constant, were higher at slower cooling rates. The internal resistance increased exponentially from the sol to the sol-gel transition at all cooling rates. The internal resistance, when the elastic moduli reached constant, was higher at slower cooling rates, which was consistent with the viscoelastic behavior. These results suggest that the progress of cross-linking of collagen molecules becomes faster as the cooling rate increases, but the degree of cross-linking when gelatinized becomes relatively lower.

Research works of controlling physical properties of mixed gellan gums, mixed carrageenas and mixed gelatins will be reported. Studies on network structures of the mixed systems by microDSC, NMR, CD and particle-trackings will be also presented.

【Purpose】This study aimed to investigate and preliminarly characterize spices with potential emulsifying ability.

【Methods】Various spices were wet-milled into pastes. The stability of spice pastes were observed through storage test. Finally, spice pastes with highest stability were further investigated physically to confirm potential emulsifying ability.

【Results】A total of 20 spices were screened, which resulted in half of the samples showing less than 1% phase separation after storage. Three spices with highest resistance to phase separation were Anise Seed, Black Cumin and Star Anise Outer fruit. Compared to unstable samples, highly stable spices showed distinct physical behaviours when subjected to various effects of heat and high salt concentrations as well as viscosity test, suggesting the potential emulsifying ability of the investigated spices.

Purpose

Stenotrophomonas maltophilia is a challenge in food industry for being a resilient spoilage bacteria due to its biofilm forming capabilities. The purpose of this research is to investigate its cross-species interactions with enterohemorrhagic Escherichia coli (EHEC) in biofilm formation, and to evaluate bacteriophage as a controlling agent.

Methods

S. maltophilia and EHEC were incubated at 30℃ for 24 h, and biofilm formation was measured using crystal violet method in 96-well plate. The composition of bacterial species in biofilms was determined by plating on both LB agar and CHROMagar selective agar. Biofilm was harvested by swabbing.

Bacteriophage was isolated from various sources, propagated, and high titer stocks were prepared. The phage was then characterized by whole genomic DNA sequencing and pH stability test.

Results

S. maltophilia showed strong ability of forming biofilm complex than that of EHEC. The biofilm amount formed corresponded to the initial ratio of S. maltophilia in the mixed biofilm with EHEC.

In the biofilm, the ratio of EHEC was low (0.2%-7%) regardless of initial inoculum. In the case of S. maltophilia and EHEC, the biofilm formation process was independent, with no mutual effects.

Two phages have been isolated from commercially-available chicken fillet (Sasami) and tail (Bonjiri). Currently the sequencing data are being analyzed. The phage isolated from Bonjiri was stable at pH ranging from 5-10, while the phage from Sasami was stable at pH ranging from 5-9.