Differences in flavor characteristics of frozen surimi products reheated by microwave, water boiling, steaming, and frying

Effects of temperature fluctuations on non-volatile taste compounds in tilapia fillets (Oreochromis niloticus)

In this study, the effect of temperature fluctuations on the taste quality of tilapia fillets during frozen storage was investigated. Major temperature-responsive factors included free amino acids (FAAs) and flavor nucleotides in fish fillets, which were identified using multidimensional infrared spectroscopy (MM-IR). The main FAA in tilapia fillets is a sweet amino acid (glycine). Compared with the control group, the umami FAAs and sweetness FAAs were significantly increased, and the total FAAs content increased to 1.30 times after the ninth fluctuation, reaching the highest level (611.16 ± 73.60 mg/100 g). Considering the equivalent umami intensity values, adenosine monophosphate and inosine monophosphate were retained during the first and second temperature fluctuations. In addition, the content of Na⁺, K⁺, and Ca²⁺ decreased (P < 0.05). Therefore, MM-IR is an effective method to identify taste components. With regard to taste quality, temperature fluctuations in the twofold range have an umami-enhancing effect.

Effect of Black Tea Powder on Antioxidant Activity and Gel Characteristics of Silver Carp Fish Balls

The effect of black tea powder on the antioxidant activity and gel characteristics of fish balls from silver carp were investigated after freezing storage for 7 days. The results show that black tea powder with different concentrations of 0.1%, 0.2% and 0.3% (w/w) could significantly increase the antioxidant activity of fish balls (p < 0.05). In particular, at the concentration of 0.3%, the antioxidant activity was the strongest among these samples, where the reducing power, DPPH, ABTS and OH free radical scavenging rate were up to 0.33, 57.93%, 89.24% and 50.64%, respectively. In addition, black tea powder at the level of 0.3% significantly increased the gel strength, hardness and chewiness while greatly reducing the whiteness of the fish balls (p < 0.05). ESEM observation found that the addition of black tea powder could promote the crosslinking of proteins and reduced the pore size of the gel network structure of the fish balls. The results suggest that black tea powder could be used as a natural antioxidant and gel texture enhancer in fish balls, which we found to be much related to the phenolic compounds of black tea powder.

Investigation of the effect of chemical composition of surimi and gelling temperature on the odor characteristics of surimi products based on gas chromatography-mass spectrometry/olfactometry

This study investigated the effects of chemical composition of surimi (prepared by 0, 1, or 2 times of rinsing) and gelling temperature (90 °C and 100 °C) on the odor characteristics of surimi products and the relationship between the chemical composition of surimi and the aroma of surimi products. The once- and twice-rinsed surimi showed a decrease (p < 0.05) of 71.32%, 74.60%, 42.79% and 61.12% in the contents of total amino acids and total fatty acids, respectively. The surimi products prepared with un-rinsed surimi at 90 °C had the highest fish-fragrance score, while those prepared with once-rinsed surimi at 100 °C showed the strongest warmed-over flavor (WOF) and the lowest fish-fragrance score.Gly, Phe, and most of the saturated fatty acids were associated with WOF formation in surimi products, while Leu, Ile, Val, Asp, and unsaturated fatty acids were positively related to their fish-fragrance note.

Decoding the Effect of Age on the Taste Perception of Chicken Breast Soup Based on LC-QTOF-MS/MS Combined with a Chemometric Approach

A nontargeted fingerprinting approach combined with the chemometrics method and sensory analysis was used to assess the differences in taste-chemical compositions of chicken breast soup with different ages and their sensory qualities. The sensory evaluation results showed that the overall taste as well as the sourness, saltiness, and umami scores of the soup were increased with the age of chicken. Fifty-nine compounds were identified from four soup samples by liquid chromatography-tandem quadrupole time-of-flight mass spectrometry (LC-QTOF-MS/MS), and their total content was the highest in the 90 wk soup samples. Six upregulated compounds (carnosine, hypoxanthine, inosine, inosine 5'-monophosphate (5'-IMP), adenosine 5'-monophosphate (5'-AMP), and lactic acid) were identified as potential contributors to the taste characteristics of the 90 wk soup samples by orthogonal projections to latent structures-discriminant analysis (OPLS-DA). Additional experiments showed that 5'-AMP particularly contributed to the sourness of the soup, while carnosine contributed to the saltiness and umami of the soup.

Characterization of non-volatile and volatile flavor profiles of Coregonus peled meat cooked by different methods

This study investigated the effects of different cooking methods on non-volatile flavor (free amino acids, 5'-nucleotides, and organic acids, etc.) of Coregonus peled meat. The volatile flavor characteristics were also analyzed by electric nose and gas chromatography-ion migration spectrometry (GC-IMS). The results indicated that the content of flavor substances in C. peled meat varied significantly. The electronic tongue results indicated that the richness and umami aftertaste of roasting were significantly greater. The content of sweet free amino acids, 5'-nucleotides, and organic acids was also higher in roasting group. Electronic nose principal component analysis can distinguish C. peled meat cooked (the first two components accounted for 98.50% and 0.97%, respectively). A total of 36 volatile flavor compounds were identified among different groups, including 16 aldehydes, 7 olefine aldehydes, 6 alcohols, 4 ketones, and 3 furans. In general, roasting was recommended and gave more flavor substances in C. peled meat.

Analysis of volatile compounds and flavor fingerprint in hairtail (Trichiurus lepturus) during air-drying using headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS)

In the present study, changes in volatile compounds during processing were analyzed using the headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS), to investigate the generation of aroma in hairtails (Trichiurus lepturus) during air-drying. Physicochemical indices, such as moisture content and thiobarbituric acid reactive substances (TBARS), were also detected. Flavor fingerprints were studied and developed to distinguish the samples of fresh hairtails (0 day) from air-dried hairtails (2 and 4 days). A total of 75 volatile organic compounds (VOCs) were identified in hairtails, in which alcohols, aldehydes, ketones, and esters were the principal contributors to the formation of the overall flavor of hairtails during air-drying. Seven flavor compounds (ethanol, 3-methyl-1-butanol, 1-pentanol, hexanal, octanal, benzaldehyde, and 3-methylbutanal), two flavor compounds (acetoin and dimethyl sulfide), and eight flavor compounds (1-hexanol, 1-octen-3-ol, nonanal, heptanal, 2-heptanone, ethyl acetate, trimethylamine, and ammonia) were identified in 0, 2, and 4 air-dried hairtails as biomarkers, respectively. The results showed that HS-GC-IMS could detect VOCs in different air-dried hairtails rapidly and comprehensively.

Metabolomics investigation on the volatile and non-volatile composition in enzymatic hydrolysates of Pacific oyster (Crassostrea gigas)

To investigate the differences of volatile and non-volatile metabolites between oyster enzymatic hydrolysates and boiling concentrates, molecular sensory analysis and untargeted metabolomics were employed. "Grassy," "fruity," "oily/fatty," "fishy," and "metallic" were identified as sensory attributes used to evaluate different processed oyster homogenates. Sixty-nine and 42 volatiles were identified by gas chromatography-ion mobility spectrometry and gas chromatography-mass spectrometry, respectively. Pentanal, 1-penten-3-ol, hexanal, (E)-2-pentenal, heptanal, (E)-2-hexenal, 4-octanone, (E)-4-heptenal, 3-octanone, octanal, nonanal, 1-octen-3-ol, benzaldehyde, (E)-2-nonenal, and (E, Z)-2,6-nonadienal were detected as the key odorants (OAV > 1) after enzymatic hydrolysis. Hexanal, (E)-4-heptenal, and (E)-2-pentenal were significantly associated with off-odor, and 177 differential metabolites were classified. Aspartate, glutamine, alanine, and arginine were the key precursors affecting the flavor profile. Linking sensory descriptors to volatile and nonvolatile components of different processed oyster homogenates will provide information for the process and quality improvement of oyster products.

Physicochemical Characteristics and Flavor Properties of Texturized Dual-Proteins Extrudates: Effect of Surimi to Soybean Flour Ratio

This study investigated the effects of surimi to soybean flour ratio (0:10, 1:9, 2:8, 3:7, 4:6) on the physicochemical characteristics and flavor properties of dual-proteins extrudates. The increasing ratio of surimi improved the color of extrudates and raised the apparent viscosity of the mixed raw materials, which led to the decrease of extrudates' thickness. The excess ratio of surimi and soybean flour (more than 2:8) was bad for extrudates' physicochemical characteristics with sharply decreased tensile strength, macroscopic longitudinal fracture, broken and unevenly distributed microstructure, increased water mobility and decreased free water content. However, the increasing ratio of surimi had no effect on the protein secondary structure of extrudates. Sensory evaluation, E-tongue and E-nose analysis suggested that adding surimi significantly changed the flavor properties of extrudates, with increased sweetness and umami taste, and an appropriate ratio (2:8 or 3:7) could reduce the beany flavor and without an obvious fishy off-flavor.

Changes in Protein Degradation and Non-Volatile Flavor Substances of Swimming Crab (Portunus trituberculatus) during Steaming

To investigate the effect of steaming time (0, 5, 10, 15, 20, and 25 min) on the protein degradation and non-volatile flavor substances of swimming crab (Portunus trituberculatus), the moisture content, total nitrogen (TN), non-protein nitrogen (NPN), free amino acids (FAAs), flavor nucleotides, electronic tongue analysis, and sensory evaluation were determined. The results showed that the contents of NPN and total FAAs were the highest after crabs steamed for 10 min. Meanwhile, the AMP (adenosine monophosphate) content reached the maximum value (332.83 mg/100 g) and the taste active value (TAV) reached 6.67, which indicated that AMP contributes the most to the taste of steamed crab at 10 min. The electronic tongue distinguished the taste difference well, and the sensory score was the highest at 15 min. Combined with equivalent umami concentration (EUC) and TAV value, swimming crab (weight = 200 ± 20 g) steamed for 10–15 min tasted best.

Impacts of agar gum and fucoidan on gel properties of surimi products without phosphate

Phosphate is widely used in surimi products to improve the gel properties. However, excess addition of phosphate occurs, which can harm the consumer's health. This study aimed to evaluate the effects of agar gum and fucoidan on maintaining the gel properties of surimi products instead of phosphate. Interestingly, our results showed that 0.125% of agar gum and fucoidan to replace phosphate could enhance water-holding capacity and maintain gel strength and textual properties of surimi products well. Especially at frozen storage for 1 year, 0.125% of agar gum reduced the expressible moisture content of surimi products by around 10% (p < .05). Sensory evaluation showed that 0.125% of agar gum and fucoidan instead of phosphate can improve tissue and fondness of surimi products in refrigerated storage for 24 h but not in frozen storage for 1 year. The addition of agar gum and fucoidan at a high concentration >0.50% increased the WHC, but significantly decreased gel strength and springiness of surimi products (p < .05). Particularly, 1.00% of agar gum and fucoidan reduced gel strength by around 20% (p < .05). It might be due to the destruction of the gel network structure of surimi protein following the excess addition of these polysaccharides. It can be concluded that 0.125% of agar gum and fucoidan can replace phosphate to develop high-quality surimi products, and excessive addition of them have negative effects.

Effects of four cooking methods on flavor and sensory characteristics of scallop muscle

This work aimed to explore the influence of four different cooking methods (Boiling, roasting, frying, and microwaving) on the sensory characteristics of scallop muscles. Headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) and electronic nose (e-nose) were combined to analyze the aroma of scallops. Combined with the results of free amino acids and electronic tongue (e-tongue), the taste changes of different samples were analyzed. Furthermore, texture profile and microstructure analysis jointly showed the influence of cooking methods on texture. The results showed that frying was the most suitable cooking method for scallop muscle because it resulted the best tasted products, boiled scallops retain the highest similarity to fresh scallops. Besides, a higher level of lipid oxidation and Maillard reaction resulted in significant increase in aldehydes, ketones, furans, umami, and sweet amino acid. For the boiled sample, the loss of water-soluble compounds and less fat oxidation resulted in fewer flavor substances and free amino acids, along with looser organizational structure and poorer sensory quality. The research showed that besides the texture of scallop muscle, volatile organic compounds and free amino acids as well as their mutual roles in taste and smell were also important to sensory receptivity.

Quality Improvement of Zhayu, a Fermented Fish Product in China: Effects of Inoculated Fermentation with Three Kinds of Lactic Acid Bacteria

To investigate the effects of inoculation fermentation on the quality of Zhayu (a traditional fermented fish product in China), different amounts of L. plantarum, P. acidilactici, and P. pentosaceus were inoculated into samples, and the safety, nutritional, textural, and flavor properties of the samples were evaluated. Fermentation with lactic acid bacteria (LAB) decreased pH values and total volatile basic nitrogen content. The addition of 10⁸~10⁹ cfu/100 g LAB significantly increased the content of crude fat and water-soluble proteins in Zhayu. The addition of L. plantarum and P. acidilactici increased the content of soluble solids in Zhayu. Moreover, fermentation with LAB made the products tender and softer, and the samples prepared with 10⁹ cfu/100 g LAB presented better overall qualities. Additionally, Zhayu fermented with L. plantarum and P. acidilactici showed the strongest sourness, while the samples prepared with P. pentosaceus showed the strongest umami taste, consistent with the highest contents of Asp (25.1 mg/100 g) and Glu (67.8 mg/100 g). The addition of LAB decreased the relative contents of aliphatic aldehydes, (Z)-3-hexen-1-ol, and 1-octen-3-ol, reducing the earthy and fishy notes. However, LAB enhanced the contents of terpenoids, acids, esters, and S-containing compounds, increasing the sour, pleasant, and unique odors of Zhayu.

Comparative Studies on the Physicochemical and Volatile Flavour Properties of Traditional Deep Fried and Circulating-Air Fried Hairtail (Trichiurus lepturus)

The aim of this study is to investigate the effects of deep frying (DF) and air frying (AF) on the quality and flavour profile of hairtail (Trichiurus lepturus) fillets. The changes of some physicochemical indices such as moisture content, oil content, colour, thiobarbituric acid reactive substances (TBARS) and peroxide values (POV) in hairtail fillets were detected with increasing frying time. According to these physicochemical indices and sensory evaluation, deep frying for 7 min under 190 °C (DF7) and air frying for 24 min under 190 °C (AF24) were selected as samples for their great quality. The flavour fingerprint of hairtail (Raw, DF7, AF24) was developed and volatile compounds were investigated by HS-GC-IMS. A total of 28 volatile substances including aldehydes, alcohols, ketones and others were identified both in the DF7 and AF24 samples. There are differences in the aroma fingerprint between the DF7 and AF24 samples. DF was characterised by 2-Heptanone, (E)-2-Heptenal, 2-Pentyfuran and 1-Pentanol, AF was characterised by 2-methylbutanol, Ethyl methyl ketone-M and 3-hydroxy-2-butanone. These findings suggest that the aroma of hairtail fillets after DF7 and AF24 was significantly different and supply flavour information and practical applications of the fried hairtail fillets.

Flavor Differences of Edible Parts of Grass Carp between Jingpo Lake and Commercial Market

This study investigated the flavor differences among three individual parts (abdomen, back, and tail) of Jingpo Lake grass carp (JPGC) and commercial grass carp (CGC). The growing environment and fish parts influenced the volatile compounds of the fish. The highest total contents of alcohols and ethers were found in the back of JPGC (p < 0.05). The combination of an electronic tongue and electronic nose (E-nose) could effectively distinguish the flavor differences between the different parts of JPGC and CGC by principal component analysis. Both the content of total free amino acids (FAAs) and content of amino acids contributing to the sweet and fresh flavors were higher in JPGC than CGC (p < 0.05). Among the ATP-associated products, the inosine 5’-monophosphate (IMP) contents of the back and tail of JPGC were higher (p < 0.05), but the abdomen content was lower (p > 0.05) than the respective contents in the corresponding parts of CGC. Sensory evaluation shows that JPGC had a better texture, odor, and taste, compared to CGC. Correlation analysis showed that the E-nose data and FAAs were highly correlated with the content of alcohols, aldehydes, and ethers. This study showed that the flavors of the different parts of JPGC differed significantly from those of CGC.

Characterization of Warmed-Over Flavor Compounds in Surimi Gel Made from Silver Carp (Hypophthalmichthys molitrix) by Gas Chromatography-Ion Mobility Spectrometry, Aroma Extract Dilution Analysis, Aroma Recombination, and Omission Studies

The warmed-over flavor (WOF) in surimi gels was characterized by gas chromatography-ion mobility spectrometry, aroma extract dilution analysis, aroma recombination, and omission studies. Surimi gels with different WOF levels were prepared by different gelling temperatures, and surimi gels heated at 90, 100, and 121 °C were considered as the samples with light, strong, and medium WOF, respectively. Based on the quantification and odor activity values, 14 aldehydes, 2 ketones, 3 alcohols, 2 benzene-containing compounds, 2 N-containing compounds, 3 S-containing compounds, 3 lactones, undecanoic acid, and 4-methylphenol were recombined to build a spiked model for surimi gels with the strongest WOF, which showed the highest similarity with the original sample. Finally, a triangle test involving omission of the aroma compounds from the spiked model proved that the WOF in surimi gels was attributed to (E,E)-2,4-decadienal, heptanal, octanal, nonanal, decanal, (E)-2-nonenal, (E)-2-octenal, (E)-2-decenal, (E,E)-2,4-heptadienal, 2,3-pentanedione, 2,6-dimethylpyrazine, 2-propylpyridine, benzothiazole, 2-methoxybenzenethiol, and 2-furfurylthiol.

Vibration mill-assisted complex enzyme hydrolysis for flavoring of freeze-dried sea cucumber powder

This study aims to analyze the flavor differences of freeze-dried sea cucumber powder, processed for different time intervals, under vibration mill-assisted complex enzyme hydrolysis using electronic nose (E-nose) and gas chromatography-ion mobility spectrometry (GC-IMS). The results of principal component analysis by E-nose showed distinction among the four groups of freeze-dried sea cucumber powder (papain-neutral protease (PN) and flavorzyme-neutral protease (FN), processed for 60 and 80 min). The GC-IMS revealed 35 volatile compounds. Subsequently, based on the fingerprint and heat map results, the flavor differences among the samples were clearly distinguished. When compared to the other three groups, the 60-FN group exhibited a greater variety and quantity of volatile compounds such as octanal, heptanal, hexanal, (E, Z)-2,6-nonadienal, and nonanal. The 80-PN group exhibited high amounts of 2-propanone, ethylbenzene, ethyl acetate, and 2,5-dimethylpyrazine. In addition, the vibration mill technique was considered to be a mild enzyme-assisted method. PRACTICAL APPLICATIONS: This study found that different enzyme types and physical technology operation time can affect the different volatile flavor compounds of freeze-dried sea cucumber powder, which can be quickly and effectively be identified by E-nose and GC-IMS technology to improve the flavor and quality of the product, while facilitating the rapid adjustment and development of the industry. Meanwhile, the results of the study could provide a reference for the deep processing and flavor improvement of the sea cucumber industry and make an important contribution to the related literature. In addition, this could also promote the development and application of non-thermal processing technologies such as vibratory mill in the freeze-dried sea cucumber powder industry.

Threadfin bream surimi gel containing squid fin protein hydrolysate: Textural properties, acceptability, and volatile profile

Gel properties of threadfin bream surimi gels with squid fin protein hydrolysate (SFPH) at various concentrations (0, 1, 2, 3, and 4%; w/w) were determined. The gel without SFPH (CON) had the highest breaking force (BrF) and deformation (DeF) as compared to those with SFPH (p < 0.05). Among the gel with SFPH, gel containing 1 and 2% SFPH (SFPH-1 and SFPH-2, respectively) had the highest BrF, whereas the lowest value was obtained when 4% SFPH was used (SFPH-4) (p < 0.05). The whiteness of all samples was slightly decreased with an upsurging amount of SFPH. However, water holding capacity was increased with augmenting levels of SFPH (p < 0.05). Sensory analysis revealed that SFPH-2 had a higher squid odor and flavor likeness score than CON (p < 0.05). Textural properties, especially hardness, were decreased with increasing SFPH, except for SFPH-1 and SFPH-2 (p > 0.05). In addition, the rheological properties, microstructure, and volatile profile of the selected surimi gel were also studied. The storage modulus (G') of SFPH added samples was decreased as compared to the CON sample. The CON gel had a finer and more compact network as compared to SFPH-2 and SFPH-4 samples. Volatile profiles indicated that alcohols, carboxylic acids, ketones, and ether were the major volatile compounds present in both gel samples. Furthermore, thiophene, 3-methyl-, contributing to squid flavor, was found in the SFPH-2 sample. Overall, SFPH at 2% could act as a flavorant in the threadfin bream surimi gel without markedly negative impact on gelling and textural properties, while providing squid odor and flavor to the resulting gel. PRACTICAL APPLICATION: The various low-valued byproducts generated from the squid processing industry could result in various environmental problems. Those byproducts are rich in various biomolecules such as proteins, fats, enzymes, and so forth, which could be utilized to produce value-added products. Among them, protein hydrolysate (PH) rich in amino acids with excellent antioxidant properties could serve as an alternative flavorant. Therefore, PH from squid byproducts, especially fins, could be applied in foods such as fish balls, surimi gels, and so forth to enhance the nutritional and flavoring profile of a finished product. Moreover, bioactive peptides in PH with antioxidant potential could retard the oxidation of proteins and lipids.

Different Thermal Treatment Methods and TGase Addition Affect Gel Quality and Flavour Characteristics of Decapterus maruadsi Surimi Products

Decapterus maruadsi surimi products were prepared using the thermal treatment methods of boiling (BOI), steaming (STE), back-pressure sterilization (BAC), roasting (ROA), microwaving (MIC), and frying (FRI), respectively. The effect of glutamine transaminase (TGase) addition was also investigated. The moisture distribution, water retention, microstructure, color, fracture constant, protein secondary structure, chemical forces, and flavor components of each sample were determined. The differences in gel and favor characteristics between D. maruadsi surimi products caused by thermal treatment methods were analyzed. The results showed that BOI, STE, and FRI had the largest protein secondary structure transitions and formed dense gel structures with high fracture constant. The kinds of flavour components in BOI and STE were completer and more balanced. The high temperature treatment available at BAC and FRI (110 °C and 150 °C) accelerated the chemical reaction involved in flavor formation, which highlighted the flavor profiles dominated by furans or esters. The open thermal treatment environments of ROA, MIC, and FRI gave them a low moisture content and water loss. This allowed the MIC to underheat during the heat treatment, which formed a loose gel structure with a low fracture coefficient. The addition of TGase enhances the gel quality, most noticeably in the ROA. The aldehyde content of the FRI was enhanced in the flavor characteristic. The effect of adding TGase to enhance the quality of the gel is most evident in ROA. It also substantially increased the content of aldehydes in FRI. In conclusion, different heat treatments could change the gel characteristics of surimi products and provide different flavor profiles. The gel quality of BOI and STE was consistently better in all aspects.