Salt-soluble Protein Extracts Research Articles

Salt-soluble protein extracts from Hermetia illucens and Bombyx mori for high protein pasta production

Black soldier fly (Hermetia illucens, HI) and silkworm (Bombyx mori, BM) are two promising insect species for possible novel food applications, currently undergoing safety evaluation by European Food Safety Authority (EFSA). Aim of this research was to extract a protein fraction from defatted insect powders using phosphate-buffered saline and to manufacture pasta by replacing 15% semolina with salt-soluble insect protein extract, in order to achieve the claim “high protein”. Pasta samples were then analysed to evaluate their technological quality. The high-protein pastas showed darker colour (L*: 52.5 < 58.4 < 72.3, for HI, BM, and CP, respectively; p < 0.05), higher fracturability (5.68 and 5.49 > 7.06 N; p < 0.05) and water absorption index (171 and 172 > 149%; p < 0.05) than control pasta. However, pasta firmness and adhesiveness remained unchanged. Black soldier fly and silkworm provide protein extracts suitable for the production of high protein pasta with good technological quality; furthermore, they might have interesting potential for other food applications.

Intrinsic Allergenicity Potential of Salt-Soluble Protein Extracts from the Diploid, Tetraploid and Hexaploid Wheats: Validation Using an Adjuvant-Free Mouse Model

Wheat allergies are potentially life-threatening and, therefore, have become a major health concern at the global level. It is largely unknown at present whether genetic variation in allergenicity potential exists among hexaploid, tetraploid and diploid wheat species. Such information is critical in establishing a baseline allergenicity map to inform breeding efforts to identify hyper-, hypo- and non-allergenic varieties. We recently reported a novel mouse model of intrinsic allergenicity using the salt-soluble protein extract (SSPE) from durum, a tetraploid wheat (Triticum durum). Here, we validated the model for three other wheat species [hexaploid common wheat (Triticum aestivum), diploid einkorn wheat (Triticum monococcum), and the ancient diploid wheat progenitor, Aegilops tauschii], and then tested the hypothesis that the SSPEs from wheat species will exhibit differences in relative allergenicities. Balb/c mice were repeatedly exposed to SSPEs via the skin. Allergic sensitization potential was assessed by specific (s) IgE antibody responses. Oral anaphylaxis was quantified by the hypothermic shock response (HSR). The mucosal mast cell response (MMCR) was determined by measuring mast cell protease in the blood. While T. monococcum elicited the least, but significant, sensitization, others were comparable. Whereas Ae. taushcii elicited the least HSR, the other three elicited much higher HSRs. Similarly, while Ae. tauschii elicited the least MMCR, the other wheats elicited much higher MMCR as well. In conclusion, this pre-clinical comparative mapping strategy may be used to identify potentially hyper-, hypo- and non-allergenic wheat varieties via crossbreeding and genetic engineering methods.

Protective effects of edible insect protein extracts from Protaetia brevitarsis against H2O2-induced oxidative stress in mouse C2C12 myoblast cells

Edible insects have been attracting significant attention not only for their nutritional superiority but also for their excellent bio-functional activity. In this study, the apoptotic protective effects of water-soluble protein (WPB) and salt-soluble protein (SPB) extracts derived from Protaetia brevitarsis against hydrogen peroxide (H2O2)-induced oxidative stress in C2C12 cells were investigated. WPB and SPB were confirmed to exhibit radical scavenging and ferric-ion reducing activities. In addition, WPB and SPB treatments effectively restored the decreased cell viability of the C2C12 cells induced by H2O2 treatment, and showcased protective effects against apoptosis and mitochondrial dysfunction by regulating the expressions of pro- and anti-apoptotic proteins. Therefore, our data indicated that protein extracts from Protaetia brevitarsis could be beneficial for the prevention and treatment of diseases associated with apoptosis induced by oxidative stress.

Comparison of sensitizing and disease-eliciting capacities of salt-soluble protein extracts from diploid (einkorn) versus tetraploid (durum) wheats

Abstract Hypersensitivity reactions to wheat have reached significant levels of global public health concern for reasons that are incompletely understood. Einkorn wheat (Triticum monococcum, genome AA) is commercially available but is rarely consumed, whereas durum wheat (Triticum durum, genome AABB) is commonly used for pasta making. At present, most mouse models of wheat allergy are adjuvant-based, which fail to reveal the intrinsic allergenic potential of different wheat products. Here we compared einkorn and durum wheats in terms of their sensitizing and disease-eliciting capacities in an adjuvant-free mouse model of anaphylaxis induced by salt-soluble protein extract (SSPE). Balb/cJ female mice were sensitized transdermally with SSPE or saline for nine weeks. Later, systemic or oral anaphylactic reactions were elicited in these mice using SSPE via intraperitoneal or oral route, respectively. We did not observe major differences in sensitizing capacity as suggested by antibody responses (i.e., sIgE and tIgE levels) in SSPE-sensitized mice. However, SSPE from durum appears to be more potent than that from einkorn in eliciting systemic but not oral anaphylaxis as shown by hypothermic shock responses as well as mucosal mast cell degranulation. This is the first report on comparing the intrinsic allergenicity between tetraploid and diploid wheats in an adjuvant-free mouse model. This research was funded by: the United States Department of Agriculture (USDA)/National Institute of Food and Agriculture (NIFA); Hatch project MICL02486 (Accession Number: 1012322), Hatch project MICL01699; Agricultural and Food Research Initiative Competitive Program, grant number: 2018-67017-27876; and Project GREEEN (Michigan State University); R.J., was supported by the John Harvey Kellogg Graduate Assistantship and the Academic Achievement Graduate Assistantship from the Michigan State University.

Analysis of transdermal sensitization and oral anaphylaxis using salt-soluble protein extracts from diploid wheats in an adjuvant-free mouse model

Abstract Wheat allergies are growing at an alarming rate for reasons that are not well understood. The commonly consumed wheats belong to the AABB and AABBDD genotypes. The AA wheat is less commonly consumed, and the DD wheat is not commercially available. It is unknown at present whether the diploid wheats elicit allergic reactions in mice. Here we tested the hypothesis that the salt-soluble protein extracts (SSPEs) from AA and DD wheats will induce food allergy in Balb/cJ male mice in an adjuvant-free model. We grew the DD wheat at our university and used it in this study. The AA wheat was obtained from www.einkorn.com. Balb/cJ male mice were bred and maintained on a plant protein-free diet. Mice were exposed to SSPEs or saline via skin once a week for nine weeks. SSPE-specific IgE (sIgE) was measured using an ELISA. After sensitization, mice were orally challenged with SSPEs or saline to elicit a hypothermia shock response (HSR). We found that both AA- and DD-SSPEs elicited significant and comparable levels of sIgE responses upon skin exposures. Oral challenge with DD-SSPE but not saline in DD-SSPE sensitized elicited a mild HSR lasting up to only 15 minutes. In contrast, oral challenge with AA-SSPE but not saline in AA-SSPE sensitized mice elicited a severe HSR lasting for 30 minutes. These data together suggest that the diploid wheats induce comparable sensitization, but DD wheat is less potent in inducing oral anaphylaxis compared to the AA wheat.

362 Utilizing Chicken Breast with Wooden Breast and White Striping in Processed Meat Products

Abstract Wooden breast (WB) and white striping (WS) are two myopathies impacting the broiler market. Wooden breast and WS may occur individually or in concert with each other. Wooden breast is characterized by increased rigidity and firmness in the pectoralis major and has been associated with breast meat from larger, faster growing broilers. It begins in the ventral-cranial region and increases in severity, moving toward the deeper and more caudal portions of the muscle. Although the etiology is not fully understood, compositional characteristics of WB include increased collagen and lipid deposition and decreased water holding capacity. Breast fillets exhibiting WS are characterized by the size and amount of striping that occurs on the surface of the pectoralis major. These breasts express similar compositional characteristics to those with WB. Both WB and WS have been associated with decreased organoleptic and rheological properties, causing industry losses estimated in excess of $200 million annually through value downgrades, trim loss, and diversion to rendering. Although WB and WS meat have decreased rheological properties, some lost value may be recaptured through further processing. Recent studies have shown that both blade tenderization and marination improved the textural properties of afflicted breast meat, but neither were able to overcome the differences between afflicted and normal breast meat. Research investigating comminuted and emulsified products containing WB or WS meat have shown similar results due to the lower extraction of salt-soluble proteins and subsequent low bind and gelation properties. When WB/WS meat was included as a portion of the meat block with normal breast meat, textural and rheological differences were ameliorated. Using WB or WS meat in further processed products may give processors an alternative use for afflicted breast meat. Additional research should continue to explore how WB and WS meat can be incorporated into further processed and value-added products.

Identification and characterization of cryoprotective peptides extracted from silver carp (Hypophthalmichthys molitrix) hydrolysates

ABSTRACT The cryoprotective effects on surimi matrix of hydrolysates with different hydrolyzing times prepared from silver carp using Protamex were compared with commercial sorbitol-sucrose cryoprotectants. Cryoprotective assays showed that FPH-30 (hydrolysate with 30 min hydrolyzing) was a more effective cryoprotectant than other hydrolysates, because the FPH-30 group displayed lower salt-soluble protein extractability loss (29.90 ± 0.84%), less actomyosin Ca2+-ATPase activity decrease (48.85 ± 2.56%) and unfrozen water content decrease (10.39 ± 0.63%) after six freeze-thaw cycles. To exploit industrial utilizations, FPH-30 was further purified with ultrafiltration membranes. The cryoprotective activity of the fraction (<3 kDa) was superior to the others by reducing the salt-soluble protein extractability loss (27.21 ± 0.98%) and impeding the actomyosin Ca2+-ATPase activity decrease (30.54 ± 1.21%). Mass spectrometry analysis showed that the fraction (<3 kDa) was mainly composed of three peptides of the sequences GVDNPGHPFIM(T) and IITNWDDMEK. The results clearly support that silver carp could be a potential source of cryoprotectant peptides for industrial applications.

Ageing-Time Dependent Changes of Angiotensin I-Converting Enzyme-Inhibiting Activity of Protein Hydrolysates Obtained from Dry-Cured Pork Loins Inoculated with Probiotic Lactic Acid Bacteria

This study aimed to determine the ageing-time dependent changes of the angiotensin I-converting enzyme (ACE)-inhibition of protein extracts obtained from LAB-inoculated dry-cured pork loins over 360 days of ageing and their hydrolysates obtained after in vitro hydrolysis and absorption. The increasing ageing time was accompanied by a growth in the ACE inhibitory activity of the water-soluble and salt-soluble protein extracts. Based on the hierarchical cluster analysis, 180 days was indicated as the optimal time for ageing of dry-cured pork loins in terms of ACE inhibition. The effect of the strain used on the ACE inhibition varied over long-term aging. The peptides generated during in vitro hydrolysis have between 6 and 22 amino acids in a sequence; the Pro, Ala, Lys, and Glu molecules comprise the largest share. This study demonstrated that pork muscle proteins may lead to production of numerous peptides with ACE inhibitory properties.

Physicochemical properties of frozen Alaska pollock fillets and surimi as affected by various sodium phosphates

The physicochemical characteristics of frozen Alaska pollock fillet and surimi were investigated as affected by various phosphates (sodium tripolyphosphate (STPP), tetrasodium pyrophosphate (TSPP), trisodium pyrophosphate, sodium hexametaphosphate, and disodium phosphate anhydrous). Both phosphate-injected fillets and phosphate-added surimi along with cryoprotectant (5% sugar and 4% sorbitol) were subjected to 0, 3, and 9 freezing/thawing (F/T) cycles. The concentration of sodium phosphate retained in fillet was adjusted to 0.3% using poking (6 times), soaking (10 min), and draining (2 min). Trimethylamine-N-oxide demethylase (TMAOase) activity and formaldehyde (FA) concentration were found significantly higher in fillet than in surimi. As STPP and TSPP were more effective to control TMAOase activity of fillet and surimi than other phosphates, during repeated F/T, lower TMAOase activity, lower FA content, lower drip/cook loss, and higher salt-soluble protein extractability were observed. Texture toughness in fillet and surimi with STPP and/or TSPP were lower than other treatments. Practical applications Two phosphates (STPP and TSPP) effectively minimized both freeze-induced and TMAOase-caused denaturation in fillets and surimi. As a result, texture toughening was reduced. TMAOase activity and FA content were significantly lower in surimi than fillets.

Comparative study of extraction efficiency and composition of protein recovered from chicken liver by acid–alkaline treatment

This study focused on the extraction efficiency and composition of proteins recovered from chicken liver after extraction by acid/alkaline solubilization (pH 2.0, 2.5, 3.0 and 3.5) and (pH 10.5, 11.0, 11.5 and 12.0) and precipitation in pH 5.5. The highest extracted protein yield was obtained at pH values of 2.0, 11.5 and 12.0 (77.9%, 78.4% and 79.3% respectively), and the lowest yield (58.5%) was obtained at pH 3.5. Extraction of salt-soluble proteins was attributed to pH 3.0 and 3.5, whereas pH 10.5, 11.0 and 11.5 extracted more water-soluble proteins. Both acidic and alkaline solubilization extracted lots of insoluble proteins. The total pigment contents achieved by acid treatment were significantly higher (P<0.05) than those by alkaline treatment. The highest total pigment content was observed at pH 2.5. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) profiles indicated higher concentrations of myosin heavy chains (MHCs) and actin by alkaline extraction than acid treatment. In one word, this method of recovering valuable protein components by acid–alkaline treatment helps to produce innovative products and leads to an increased consumption of chicken liver by humans.

Proximate and biochemical characterization of burrito (Bachydeuterus auritus) and flying gurnard (Dactylopterus volitans).

With limited protein resources and depleting commercial fish species there is the need to improve utilization of some of the lesser known species which are underutilized, for example, big eye grunt (burrito), Bachydeuterus auritus, and the flying gurnard (Dactylopterus volitans), (other names Cephalocanthus volitans (local) Pampansre). This study was to characterize some of the proximate and biochemical properties of burrito and the flying gurnard so as to evaluate their potential for use in human nutrition and other value‐added products. Proximate and chemical analysis were determined by the methods of AOAC. Fatty acid profiles were determined following the method of Saaed and Howell (1999). Amino acid profiles for the species were determined according to Bidlingmeyer et al. (1987). The protein content of both the water soluble and salt soluble protein extracts of the fish species were determined by the Bradford Protein Assay method (Bradford 1976). Rancidity of the fish species was assessed by thiobarbituric acid reactive substances (TBARS) and Peroxide value (PV) as described by Saeed and Howell (1999). Burrito contained 18% protein, whereas the flying gurnard contained 22.3%. Calcium content was 296 mg/100 g for burrito and 185 mg/100 g for flying gurnard, whereas iron content was 4.1 mg/100 g and 1.0 mg/100 g for burrito and the flying gurnard, respectively. Palmitic acid (C16) was 27% and 14.3% for the flying gurnard and burrito, respectively. C17: 1ω8 was 3% in the flying gurnard and 0.2% in burrito. Oleic (C18:1ω9) was 17% in the flying gurnard and 6% in burrito. C20:4ω6 was 1.6% in the flying gurnard and 3% in burrito. Docosahexaenoic acid (C22:6ω3) was 4.9% in the flying gurnard and 4.0% in burrito. Both burrito and the flying gurnard are of high nutritional quality as they had a high protein content, good general amino acid profile and abundance of polyunsaturated fatty acids.

Rheological and Textural Properties of Sodium Reduced Salt Soluble Myofibrillar Protein Gels Containing Sodium Tri‐Polyphosphate

AbstractThe effect of partial replacement of NaCl (50%) with KCl in the presence of sodium tri‐polyphosphate (STPP) on the cooking loss (CL), water‐holding capacity (WHC), rheological and textural properties of salt soluble myofibrillar proteins (SSMP) gels was investigated. KCl substitution, either alone or in combination with STPP, was found worse than NaCl alone in terms of elasticity of the gels (G′). Both KCl and STPP reduced the CL of the gels. While the gels with replacement of NaCl with KCl had lower (P &lt; 0.05) WHC, addition of STPP to this gels gave rise to similar (P &gt; 0.05) WHC to only NaCl added gels. Substitution of NaCl with KCl resulted in a decrease in hardness of gels whereas STPP addition improved the hardness. Results obtained from the present study suggest that substitution 50% of NaCl with KCl in presence of STPP would be a sound salt reduction alternative in meat systems.Practical ApplicationsSalt is one of the most crucial ingredients affecting meat products functionality. However, recent research has focused on reducing salt in meat products due to its association with some health problems such as hypertension. Reducing sodium chloride (NaCl) decreases extractability of salt soluble myofibrillar proteins (SSMP), thus, negatively affects functional properties of the meat systems. One of the approaches in reducing salt is to replace NaCl with other chloride salts, the most common of which is potassium chloride (KCl). This study focused on determining the effect of partially substituting of NaCl with KCl in the presence of sodium tri‐polyphosphate (STPP) on some functional characteristics of meat SSMP gels. Results indicated that 50% NaCl reduction using KCl and STPP could be achieved with an improvement of textural and functional properties in meat gels. Future research should focus on combined effects of salt substitutes on the rheological and textural characteristics of meat gel systems.

Biochemical Changes in Dressed Priacanthus hamrur (Bull’s Eye) During Frozen Storage and Its Effect on Physical and Sensory Quality of Fish Sausage

In the present investigation, biochemical changes in dressed and frozen stored Priacanthus hamrur and their influence on quality of fish sausage have been studied. During the frozen storage period of five months, moisture content decreased and led to the increment on other proximate constituents due to percentage balance. Quality indices such as total volatile base nitrogen and trimethyl amine nitrogen increased significantly (P < 0.05) and reached 44.80 mg N/100 g and 22.00 mg N/100 g of meat, respectively. Non-protein nitrogenous contents were found to decrease due to the loss in thaw drip. Lipid freshness parameters such as peroxide value and free fatty acid value increased and resulted in reduced extractability of salt soluble proteins. Gel strength of fish sausage decreased significantly (P < 0.05) during the storage period and this was also supported by the folding test. Increments in the expressible moisture content clearly indicated the loss of protein functionality, like water holding ability, due to denaturation during frozen storage. From the sensory evaluation, dressed P. hamrur can be stored frozen without any cryoprotective and preservative agents up to four months when it is intended for the preparation of fish sausage and this was also evidence from the changes in biochemical constituents.

Reduced functionality of PSE-like chicken breast meat batter resulting from alterations in protein conformation

The objectives of this study were to evaluate protein thermal stability, water-protein interaction, microstructure, and protein conformation between PSE-like and normal chicken breast meat batters. Sixty pale, soft, and exudative (PSE)-like (L*>53, pH24 h<5.7) and 60 normal (46<L*<53, 5.7<pH24 h<6.1) chicken breast meats were selected from 3 different occasions in a major Chinese commercial plant. Two different meat batters were formulated to 14% meat protein and 2% salt, and they were analyzed for the protein changes and the microstructure using differential scanning calorimetry, low-field (LF)-NMR, SEM, and Raman spectroscopy. PSE-like meat batter had lower gel strength, water-holding capacity, and salt-soluble protein extraction (P < 0.05). Heated PSE-like meat batter formed an aggregated gel matrix, while normal meat batter produced a compact gel network with fine, cross-linked strands by many protein filaments. LF-NMR revealed an increase in the water mobility in heated PSE-like meat batter with an increasing amount of loosely bound water (P < 0.05). No significant changes were observed in the electrophoretic patterns of salt-soluble protein extracts by SDS-PAGE. However, differential scanning calorimetry showed that PSE-like meat had greater myosin and sarcoplasmic proteins/collagen denaturation (P < 0.05). In PSE-like meat, actin denaturation was particular evident after salt addition (P < 0.05) using differential scanning calorimetry. Moreover, Raman spectroscopy indicated that PSE-like meat batter had less unfolded α-helix and β-sheet structure formation, reduced exposure of hydrophobic and tyrosine residues (P < 0.05), and changes in the microenvironment of aliphatic residues and tryptophan, which affected salt-soluble protein extraction, gel properties, and water-holding capacity. In conclusion, the inferior functional properties of PSE-like meat were attributed to not only myosin denaturation, but also actin denaturation after salt addition and different protein structural states.

Varying the Temperature of the Liquid Used for High‐Pressure Processing of Prerigor Pork: Effects on Fresh Pork Quality, Myofibrillar Protein Solubility, and Frankfurter Textural Properties

The objective was to evaluate high-pressure processing (HPP) with varying liquid (water) temperatures on pork quality and textural properties of frankfurters. HPP pressurization liquid temperatures were 15.5 °C (HPP Low) and 29.4 °C (HPP Med). Analyses were conducted using paired boneless loins and paired boneless hams. Loins were evaluated for pH, purge loss, objective color, subjective color, firmness; and changes in color after a bloom period. Eight independent batches (2 batches each of HPP Low, paired untreated, HPP Med, and paired untreated) of frankfurters were manufactured from the outside portion of the ham and the knuckle. Both HPP treatments resulted in higher (P < 0.05) ultimate pH and less (P < 0.05) purge loss of the loin. Loin tenderness was not different among either HPP treatment temperature groups when compared to untreated controls except HPP Med chops were more tender (P = 0.02) than untreated controls. Salt-soluble protein extractability of inside ham muscles was lower (P < 0.05) for both HPP treatment levels when compared to untreated controls, but was not different between the 2 HPP treatment levels. Textural properties of frankfurters were not different for either HPP treatment group when compared to its respective untreated control for any parameter except springiness. HPP Low frankfurters had lower (P = 0.10) springiness values than untreated controls. Fracturability of HPP Med samples was lower (P = 0.12) than untreated controls. Overall, HPP caused higher ultimate pH and increased water-holding capacity, but did not affect tenderness of fresh meat or textural properties of frankfurters. HPP can be used on prerigor pork as means to improve fresh pork quality. Loins from HPP-treated pork sides had higher ultimate pH values and less package purge loss. Tenderness values were not affected positively or negatively by HPP treatment. The high pH and water-holding capabilities of treated samples have positive implications for further processing applications. Frankfurter textural properties suggest emulsified products can be made with pressurized pork without sacrifice to the textural profile.

Effect of ammonium hydroxide on ultrastructure and tenderness of buffalo meat

This study was conducted with an objective to improve the tenderness of tough buffalo meat using ammonium hydroxide. Buffalo meat chunks from Biceps femoris muscle were marinated with distilled water (control), 0.1%, 0.5% and 1.0% solution of ammonium hydroxide for 48 h at 4 ± 1 °C and subjected to various physico-chemical analysis and ultrastructural studies. Ammonium hydroxide increased ( P < 0.05) the pH, water holding capacity (WHC), collagen solubility, total and salt soluble protein extractability and cooking yield. Reduction ( P < 0.05) in Warner–Bratzler shear force values were observed in all ammonium hydroxide treated samples compared to non-treated control. Electrophoretic pattern of muscle proteins exhibited reduction in the intensity and number of certain protein bands for 0.1% and 0.5% ammonium hydroxide treated samples compared to control. Scanning and transmission electron microscopy also revealed breakdown of endothelium layers surrounding muscle fibers and weakening of Z-discs respectively, in treated samples compared to controls. These results suggest that ammonium hydroxide might be used to tenderize tough buffalo meat.

멸치 염용성 단백질 추출물 첨가가 소시지의 품질에 미치는 영향

멸치의 염용성 단백질 추출물을 5 및 10% 농도로 첨가하여 제조한 소시지의 저장성, 품질 및 관능적 특성을 조사하였다. 소시지를 제조 후 10℃에서 35일간 저장하면서 저장성을 알아본 결과, 생균수 및 VBN 함량은 첨가구와 무첨가구 사이에 큰 차이를 보이지 않아 추출물이 소시지의 품질에 영향을 주지 않았다. 또한 멸치의 염용성 단백질 추출물이 소시지의 품질에 미치는 영향을 알아보기 위해 유화안정성, pH, 수분함량, 색도 및 물성을 측정하고 관능평가를 실시하였다. 그 결과, 유화안정성, pH, 수분함량 및 색도는 저장기간 동안 첨가구와 무첨가구가 유사한 값을 나타내었다. 물성측정 결과, 경도는 염용성 단백질 추출물 첨가 농도가 높아짐에 따라 유의적으로 증가하였으며, 검성은 5% 첨가구가 가장 높은 값을 나타내었다. 반면 10% 첨가구는 검성, 씹힘성, 응집성 및 복원성에서 유의적으로 가장 낮은 값을 나타내었다. 관능평가 결과에서는 5% 첨가구가 외관의 형태 및 탄력성 항목에서 유의적으로 가장 높은 평가를 받았다. 이상의 결과를 종합해볼 때, 소시지에 멸치 염용성 단백질 추출물을 5% 정도 첨가할 경우 무첨가구와 비교 시 조직감이 향상되고 관능적 선호도에서 탄력성이 좋은 평가를 받아 소시지의 결착력이 증진됨을 알 수 있었다. 따라서 멸치 염용성 단백질을 소시지에 첨가 시 품질향상과 더불어 단순한 가공 형태가 아닌 새로운 멸치 가공방법으로 차별성이 있으며, 저급 멸치의 사용으로 가격 경쟁력도 가지게 되어 제한된 멸치의 이용을 확대시킬 수 있을 것으로 기대된다.

2D-DIGE analysis of rice proteins from different cultivars

The 2D-DIGE (2-Dimensional Fluorescence Difference Gel Electrophoresis) method was applied to proteomic phenotyping of natural variants in 10 varieties of rice (Nipponbare, Koshihikari, Sasanishiki, Akitakomachi, Hitomebore, Hinohikari, Kasalath, Rexark, Bleiyo, Cho-ko) from the world rice collection (WRC) in the GenBank of the National Institute of Agrobiological Sciences (NIAS), Japan. Salt-soluble protein extracts of Nipponbare brown rice were labeled with Cy2 fluorochrome and used as an internal standard. Protein extracts from nine other rice varieties were labeled with Cy3 or Cy5 fluorochrome and applied to 2D-PAGE (13 cm gel length) analysis. Approximately 700 spots of rice proteins were observed. Fluorescence intensities of each of these spots for the nine rice varieties were expressed as relative ratios to that of Nipponbare. Statistical analysis revealed the spot numbers of five Japanese rice varieties above threshold five (relative ratio of each variety to Nipponbare exceeded 5-fold or was less than 1/5) to be less than three, while those of four varieties from other countries were more than five (especially, Kasalath which was 29 and Bleiyo which was 23). The 2D-DIGE method seems to be useful for analyzing natural varieties of different cultivars and also for comparing the expression of allergen proteins.

Thaumatin-like protein and baker's respiratory allergy

Baker's asthma and rhinitis are among the most common occupational diseases. Inhaled cereal flours, such as wheat, especially cause this disease. To identify and test in vivo clinically important wheat allergens in baker's respiratory allergy in a Finnish population. Potential wheat allergens were purified using chromatographic methods from salt-soluble protein extracts of wheat flour and were used in skin prick tests with serial 10-fold dilutions (0.5-0.005 mg/mL). Twenty patients with baker's rhinitis, asthma, or both participated in this study. All the patients had positive skin prick test reactions and specific IgE antibodies to wheat flour. The control group consisted of 10 healthy individuals. Molecular identities of purified wheat allergens were characterized using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and tandem mass spectrometry. Allergen concentrations of 0.3-0.5 mg/mL revealed that 12 patients reacted to a-amylase inhibitor (alpha-AI), 9 to peroxidase I (PI), 9 to thaumatin-like protein (TLP), and 6 to lipid transfer protein 2G (LTP2G). Conversely, with allergen concentrations of 0.05 mg/mL, 5 patients responded to alpha-AI, 3 to PI, 4 to LTP2G, and 6 to TLP. Of these, TLP and LTP2G are now observed to be new allergens associated with baker's asthma. In addition to the earlier-described alpha-AI and PI, TLP and LTP2G are important in vivo wheat allergens in baker's allergies in Finland. Further studies are needed to elucidate the role of these novel wheat allergens in respiratory disorders.

Capillary electrophoresis for bovine and ostrich meat characterisation

The objective of this study was to characterise, compare and quantify the water soluble protein (WSP) and salt soluble protein (SSP) fractions from bovine and ostrich muscle by using sodium dodecyl sulphate polymer-filled capillary gel electrophoresis (CE-SDS). Samples were raw ostrich leg and eye round beef collected 24 and 48 h, respectively, after sacrifice from local slaughter houses. WSP were extracted with cold double distilled deionized water and SSP with 0.6 M NaCl/0.01 M phosphate buffer pH 6 with 0.5% polyphosphates. Separation of WSP and SSP extracts was achieved by CE-SDS. Quantitative data for individual proteins was generated by constructing a calibration curve using bovine serum albumin (BSA) as a standard. The WSP profiles showed differences for bovine and ostrich meat, both qualitatively and quantitatively and could be employed for species differentiation. Quantitative data derived for WSP and SSP from bovine and ostrich muscle showed significant differences among individual proteins. A comparison of protein profiles form ostrich and bovine meat should be useful for meat species differentiation and muscle characterisation for establishing relations to meat quality.