Comparison of non-volatile umami components in chicken soup and chicken enzymatic hydrolysate

Changes in taste substances during fermentation of fish sauce and the correlation with protease activity

Anchovy sauce shows different taste profiles under different fermentation time. The change rules of free amino acids was measured by amino acid analyzer, and other taste substances, such as nucleotides and organic acids in anchovy sauce under different fermentation time were also investigated. Moreover, the correlation between protease activity and taste substances in anchovy sauce fermentation was analyzed by orthogonal partial least squares. Throughout the fermentation process, the taste substances in anchovy sauce increased during early months and then decreased as time increased. The content of amino acid nitrogen, TCA-soluble peptides, 5'-nucleotides (AMP, GMP, IMP) and organic acids (lactic acid, succinic acid) in anchovy sauce increased by 26%, 33%, (45%, 35%, 68%) and (27%, 2%) respectively in comparison with 6 months fermentation. Total amino acid content reached its maximum after 18 months fermentation. Results of electronic tongue demonstrated that the umami of anchovy sauce after 12 months fermentation increased by 17% in comparison with 6 months fermentation. A model correlating changes in protease activity with taste formation suggested that protease activity impacted the content of Ala, Glu, Lys, Asp, Leu, TCA-soluble peptides and succinic acid. This study can provide empirical evidence to guide the efficient processing of anchovy sauce.

Taste improvement of Maillard reaction intermediates derived from enzymatic hydrolysates of pea protein

Maillard reaction intermediates (MRIs) derived from enzymatic hydrolysates of pea protein, mainly initial Maillard reaction products, were prepared at a low temperature (80 °C) and the reaction time was determined by variable-temperature Maillard reaction. Electronic tongue and sensory evaluation were used to analyze the taste qualities of pea protein hydrolysates and their MRIs. Both evaluations showed that bitterness of enzymatic hydrolysates of pea protein reduced but umami taste increased through Maillard reaction. The intensities of umami and saltiness were positively correlated with the concentration of MRIs. Even when the dosage of MRIs was 0.1% (w/w), MRIs could achieve a 20% reduction in NaCl content without decreasing saltiness, which could be great potential substitutes for salt reduction. On the other hand, the increased MRIs promoted aldosterone secretion in saliva, which might enhance human perception of saltiness.

Characterization of the taste compounds in 20 pungent spices by high-performance liquid chromatography

High-performance liquid chromatography was used to determine the important taste compounds in 20 pungent spices commonly used in food, including seventeen free amino acids, four 5′-nucleotides and twelve organic acids. The equivalent umami concentration (EUC) and taste activity value (TAV) of the analyzed samples were calculated. The results showed that the content of total free amino acids ranged from 0.57 to 46.67 g/kg in 20 pungent spices. The content of total free amino acids in horseradish was the highest. The content of total 5′-nucleotides ranged from 0.80 to 4.30 g/kg, and chive contains the highest 5′-nucleotide content. Inosine 5′-monophosphate was detected in all 20 pungent spices. The content of total organic acids ranged from 9.37 to 339.58 g/kg. The total organic acids content of fieldmint was the highest (339.58 g/kg). Oxalic acid was detected in 18 pungent spices, except white pepper and chilli. The EUC of fieldmint (37.1 g MSG/100 g) was the highest in all 20 pungent spices, followed with peppermint (24.5 g MSG/100 g), and horseradish (18.4 g MSG/100 g). The TAVs of malic acid, lactic acid and 5′-AMP were higher than 1 in more than 10 spices. Lactic acid were higher than 1 in 13 spices, implying these compounds contributed greater to the flavor of pungent spices. The results of this work will provide references for the application value of pungent spices.

Investigation of Taste-Related Compounds and Antioxidative Profiles of Retorted Samgyetang Made from Fresh and Dried Cordyceps militaris Mushrooms

This study was performed to investigate the effects of taste-related compounds and antioxidatve profiles of retorted samgyetang made from fresh and dried Cordyceps militaris (C. militaris) mushrooms. A total of 48 carcasses were prepared from commercial broilers (CB; Ross, 4 weeks old) and randomly distributed into eight different treatments. Each treatment group consisted of 6 chicken carcasses made with the addition of broth in different condition and concentration of C. militaris mushrooms. The addition concentration was based on the broth volume (v/w) under either fresh or dried conditions ranging from 0% as a control to 1%, 2%, and 3% of C. militaris mushrooms. C. militaris mushrooms contributed to an improvement of meat tenderness and the antioxidative profile that led to a greater suppression of lipid oxidation. The addition of C. militaris mushrooms at 2% could also enrich the flavor and taste-related compounds, particularly the increase in 5'-AMP and umami-related free amino acid compounds, L-aspartic acid and L-glutamic acid. Different addition forms of C. militaris mushrooms, particularly fresh or dried mushrooms, had only small effects on bioactive compounds, where the dried addition could possibly enrich samgyetang broth with higher cordycepin and adenosine contents than the fresh addition. Besides, the addition of C. militaris mushrooms in the dried form could also contribute to a higher antioxidative profile. Eventually, the addition of C. militaris mushrooms with a minimum addition of 2% contributed to an improvement of meat quality, antioxidative profile and flavor improvement of samgyetang.

Optimization of beef broth processing technology and isolation and identification of flavor peptides by consecutive chromatography and LC-QTOF-MS/MS

To investigate the flavor peptides of beef broth obtained under optimized stewing conditions, separation procedures such as ultrafiltration, Sephadex G-15 column chromatography, and reversed-phase high-performance liquid chromatography were employed to isolate the umami taste peptides. Sensory evaluation was combined with liquid chromatography-mass spectrometry to detect the flavor peptides. The optimization of the stewing process conditions was studied using the orthogonal method, which indicated that time had the most significant effect on the taste efficiency of sensory evaluation, followed by the mixed spices, sucrose, and salt. The optimized cooking conditions included 3.5 hr of cooking time, 1.800 g of sucrose, 2.125 g of salt, and 1.500 g of mixed spices. The results showed that six peptides, including SDEEVEH, AEVPEVH, GVDNPGHP, GSDGSVGPVGP, SDGSVGPVGP, and DEAGPSIVH, were detected in sample X1M1; and seven peptides, including VAPEEHPT, VVSNPVDIL, VGGNVDYK, PFGNTHN, EAGPSIVHR, VDFDDIQK, and DEAGPSIVH, were detected in sample X2M2. This study compared the flavor peptides in stewed beef before and after the optimization, and thus provided a basis for the improvement of beef processing technology.

Determination of free amino acids, organic acids, and nucleotides in 29 elegant spices

Spices can be used in cooking to enhance the flavor of food. In order to systematically summarize and discuss the flavor components of 29 elegant spices, the free amino acids, nucleotides, and organic acids in these spices were detected by high-performance liquid chromatography. Cluster analysis was carried out to classify the 29 elegant spices based on similar data. The results showed considerable variations in the total free amino acids (1.12‒31.59 g/kg), organic acids (9.63‒71.90 g/kg), and nucleotides (0.03‒2.72 g/kg) in the elegant spices. Nine of the amino acids, especially glutamic acid and arginine, were found to have a taste active value (TAV) greater than 1. The TAVs of the 5'-nucleotides, succinic acid, oxalic acid, tartaric acid, and ascorbic acid were all >1. The equivalent umami concentration (EUC) of sweet marjoram was 83.69 g MSG/100 g. The 29 elegant spices were divided into two categories according to cluster analysis of the EUC. Oregano fell into one category, and the remaining 28 spices fell into the other category.

Effects and mechanism of ultrasound pretreatment of protein on the Maillard reaction of protein-hydrolysate from grass carp (Ctenopharyngodon idella)

The effects of two types (energy-divergent/gathered) of ultrasound pretreatment of protein on the Maillard reaction of protein-hydrolysate from grass carp (Ctenopharyngodon idella) were studied. The test and analysis of Fourier transform infrared spectroscopy, surface hydrophobicity and atomic force microscopy of protein, peptide concentration, molecular weight distribution and free amino acid content of protein-hydrolysate were performed to reveal the mechanism. Also, the sensory characteristics of Maillard reaction products were evaluated. Results showed that Maillard reaction products presented higher absorbance value at 294 and 420 nm after pretreated by two types of ultrasound compared to that of control. The grafting degree value of products pretreated by energy-divergent ultrasound increased by 13.87%. Both of these two types of ultrasound pretreatment showed higher (p < 0.05) value of grafting degree compared to that of positive control (thermal denaturation). The random coil content and surface hydrophobicity of protein improved significantly (p < 0.05), and the depth distribution of protein molecules narrowed down after pretreated by ultrasound, especially energy-divergent type ultrasound. The change of protein structure increased small molecular peptide/amino acid content in protein-hydrolysate, so that it promoted the Maillard reaction process of protein-hydrolysate and glucose. The mouthfulness and overall acceptance of Maillard reaction products increased after pretreated by two types of ultrasound. Results indicated that ultrasound, especially energy-divergent type ultrasound pretreatment of protein was an effective method to promote Maillard reaction evolution of protein-hydrolysate from grass carp protein and improved the flavor of Maillard reaction products.

Enzymatic hydrolysis pretreatment for enhancing the protein solubility and physicochemical quality of Cordyceps militaris chicken soup

Chicken soup is one of the most popular Chinese-style soups due to its high nutritional value and special flavor. However, the nutrients, mainly soluble protein, in the soup are relatively low. The aim of the present work was to enhance the protein solubility and other physicochemical properties of Cordyceps militaris chicken soup by enzymatic hydrolysis pretreatment. Results indicated that the soluble protein dissolution rate and flavor nucleotides (I+G) of Cordyceps militaris chicken soup had 1.6-fold and 0.5-fold increase, respectively, after enzymatic hydrolysis pretreatment. Not only the contents of total amino acids (TAA) and essential amino acids (EAA) in Cordyceps militaris chicken soup significantly increased, the organoleptic quality was also markedly improved after the enzymatic hydrolysis pretreatment. The present work provides a potential approach, which is enzymatic hydrolysis pretreatment of chicken meat, to enhance the protein solubility and physicochemical quality of Cordyceps militaris chicken soup.

Sensory attribute and antioxidant capacity of Maillard reaction products from enzymatic hydrolysate of bovine bone marrow extract

Abstract

Maillard reaction and Maillard reaction products (MRPs) are commonly used in food industry, with various sensory and functional properties. Bovine bone marrow extract (BBME) was subjected to enzymatic hydrolysis, followed by the Maillard reaction to enhance its sensory attributes. The antioxidant and antihypertensive activities of BBME, its hydrolysate and their MRPs were assessed. (3⁷) orthogonal experimental design was used to obtain the optimal reaction conditions for generation of MRPs with improved sensory characteristics. The optimal conditions were: processing temperature, 120 °C; processing time, 60 min; xylose concentration, 2.5% (w/v); cysteine concentration, 2%; Vitamin B1, 1.2%; Hydrolyzed vegetable protein, 6%; and sample to liquid ratio, 1:1. The total content of free amino acid in BBME decreased from 86.18 to 25.50 g L^-1 in EH-BBME-MRPs. In addition, EH-BBME and EH-BBME-MRPs contained significantly higher amount of low molecular weight peptides (< 1000 Da; 47.2% and 21.84%, respectively) compared to other samples. They also exhibited enhanced antioxidant activities against DPPH, ABTS and hydroxyl free radicals, and presented improved FRAP activity and reducing power. EH-BBME-MRPs also exhibited higher antihypertensive activity compared to other samples. The results indicate that MRPs derived from BBME hydrolysate are promising components for improving food flavor and also provide health benefits.

Graphic abstract

Comparison of taste components in stewed beef broth under different conditions by means of chemical analyzed

The aims of this study were to investigate the effect of stewing process on the content of taste compounds in stewing beef broth. The amino acids, 5'-nucleotides, and organic acids in stewing beef broth were determined by HPLC. The results showed that the contents of four 5'-nucleotides in raw beef were significantly lower than that in stewed beef broth. The addition of spices, salt, and sucrose was beneficial to promote the release of amino acid in beef broth. The highest contents of umami, sweet amino acid, and total amino acid were 907.67, 2930.11, and 5088.76 μg/g in stewed beef broth with salt addition, and 1085.10, 3367.48, and 5595.20 μg/g with sucrose addition. The contents of those in the stewed beef optimal group (s-b-o) were 7008.53, 34007.67, and 49282.82 μg/g, respectively, which was far higher than that with salt addition and sucrose addition. The content of total amino acid and total organic acid was significantly higher in s-b-o-o than in s-b-o. The proper amount of blend oil was beneficial to the release of flavor substances in stewed beef broth. The EUC value of the stewed beef blank group (s-b-b) was 3.50 g MSG/100 g. The addition of spices could significantly increase the EUC of stewed beef broth. The TAVs of 8 compounds were more than 1 in the sample of s-b-o-o, including Asp, Glu, Pro, Ala, Val, Met, Arg, and tartaric acid. These 8 compounds contribute more to the taste of stewed beef broth.

Effect of Salt Addition Time on the Nutritional Profile of Thunnus obesus Head Soup and the Formation of Micro/Nano-Sized Particle Structure

In order to investigate the effects of salt on the nutrients and tastes profiles of big eye tuna head soup, the typical nutrients and taste substances were analyzed. The formation and the morphology of micro/nanoparticles (MNPs) were studied using an inverted optical microscope, and the interactions among components in MNPs were studied using a laser scanning confocal microscope. The results showed that the nutrients were dissolved to the maximum in the soup when salt was added at 150 min of cooking. Comparatively, much smaller MNPs with a more stable bilayer were formed at the same salt addition time. Meanwhile, Cl- was found to permeate throughout the core and Na+ bonded with glycosylated molecules, which were dispersed around much smaller MNPs. These results suggested that in addition to promoting the migration of nutrients and taste substances, NaCl also participated in the formation and stability of MNPs in fish head soups.

Effects of three types of bone marrow extracts treated with different treatment methods on the taste of chicken soup

Bone marrow extracts (BME) are good flavor enhancing substance. Three types of BME (from porcine, chicken and bovine) were treated by enzymatic hydrolysis or Maillard reaction. To explore their effects on soup taste, they were added into chicken and non-chicken soups. The contents of free amino acids, nucleotides, peptides and soluble solids in the soup were measured and the taste activity value and equivalent umami concentration value were calculated, in addition to sensory evaluation. These parameters were weighted according to a certain ratio. Most taste-active substances increased upon enzymatic hydrolysis, while reached their maximum values after Maillard reaction. In addition, the presence of chicken alleviated bitter and fatty tastes in soups added with bone extracts, thus causing the soup to be more flavorful. Sensory evaluation results revealed that umami and kokumi tastes of soups supplemented with Maillard reaction-treated bone marrow extracts were more intense.

Isolation and identification of the umami peptides from shiitake mushroom by consecutive chromatography and LC-Q-TOF-MS

Umami is critical to the taste of shiitake mushroom. To isolate and identify umami peptides, fractions from hydrolyzed dried shiitake mushroom were separated by ultrafiltration, gel filtration chromatography (GFC), and reversed-phase high-performance liquid chromatography (RP-HPLC). Separations were combined with sensory evaluations (grading and taste dilution analysis) and analysis of electronic tongue, which were used to identify the most umami component in shiitake mushroom. Low-molecular-weight fractions (MW < 3 kDa) have the strongest flavor in the shiitake mushroom hydrolysate. In the 3 subfractions separated from low-molecular-weight fractions (MW < 3 kDa) by GFC, the second subfraction (F2) was selected for RP-HPLC analysis. The first peak (G1) in RP-HPLC was identified by LC-Q-TOF-MS, and 2 tripeptides and 3 dipeptides were identified. The amino acid sequence of these peptides were Gly-Cys-Gly, Glu-Pro-Glu, Cys-Met, Val-Phe, and Gly-Glu.