Search

As one of the most appealing edible mushrooms, the quality of Flammulina velutipes can be affected by the cultivation substrate, which has an impact on the mushroom umami taste and nutrients. In our study, the effect of mushroom root fermentation broth (MRFB) based substrate on umami taste and nutrients of F. velutipes were evaluated; four proportions of MRFB were conducted (CK 0%, E1 6.7%, E2 13.4%, E3 20.1%). Results indicated that MRFB was an effective nutrient supplement for mushroom cultivation substrate. E2 and E3 showed higher crude fiber, crude fat, and soluble protein. Compared to CK, the content of monosodium glutamate-like (MSG-like) amino acids, essential amino acids, total amino acids, and total 5′-nucleotides in E2 and E3 were higher. The equivalent umami concentration (EUC) values in E1, E2 and E3 were 1.70, 2.43 and 1.56 times that of CK, respectively. Higher umami, saltness and sweetness taste values were found in E2. Thereby, it signified that better umami and richer nutrients were achieved by using substrate with proper volume of MRFB, especially, E2 with 13.4% of MRFB. Overall, better mushroom quality could be derived from the application of MRFB in cultivation. MRFB was a favorable nutrient supplement for F. velutipes cultivation substrate.

The molecular mechanisms of energy status related to the umami taste of postharvest shiitake mushrooms during spore release remain poorly understood. In this study, the variations of energy status and umami taste of mushrooms were measured at 25 °C. At 24 h storage, slight spore prints of mushrooms were first pictured, respiration peaked. Significant ATP decrease and ADP increase were also observed as the initiation of postharvest senescence (P < 0.05). Meanwhile, the activities of phosphohexose isomerase, succinate dehydrogenase, glucose-6-phosphate dehydrogenase and cytochrome c oxidase and the contents of umami nucleotides and amino acids were maintained at higher levels in mushrooms with spore release. Notably, the equivalent umami concentration (EUC) was strongly correlated with energy levels (R = 0.80). Fifteen related gene expression levels in the energy metabolism pathway were downregulated. LecpdP1 and LeAK were significantly expressed in the conversion of ATP into AMP and played key roles in connecting the energy state and umami level. These results provided valuable insights on the umami taste associated with energy metabolism mechanism during postharvest mushroom spore release.

This study was aimed to compare the effects of thermal treatment (70, 90 ℃) and non-thermal treatment (room temperature, ultrasound treatment, homogenization and high hydrostatic pressure) on the umami taste and antioxidant capability of water extracts of Morchella esculenta. The content of 5’-nucleotide (5’-CMP, 5’-UMP, 5’-XMP, 5’-GMP, 5’-IMP and 5’-AMP) and free amino acid (17 kinds) in these extracts were analyzed by high performance liquid chromatography and amino acid analyzer respectively, and their corresponding value of Equivalent Umami Concentration (EUC) were calculated. Antioxidant properties of each water extract of Morchella esculenta were comprehensively evaluated by DPPH, FRAP and ABTS methods. Except for the treatment of RT (room temperature), other treatment on finely pulverized Morchella esculenta powder (P2 or P3, 35.52 and 6.28 μm, respectively) increased the contents of total 5'-nucleotides while decreased the contents of umami amino acids and total free amino acids (FAA) in their corresponding water extract. Therefore, the EUC values of the Morchella esculenta extracts were changed from 106.58 g MSG/100 g~493.97 g MSG/100 g to 74.70 g MSG/100 g~364.35 g MSG/100 g. Compared with the room temperature treatment, other treatments improved the EUC value of the water extracts. However, thermal treatment decreased the antioxidant capacity of the extract, and non-thermal treatment of HHP displayed the highest EUC value and ideal antioxidant effect. Especially, the original Morchella esculenta powder without superfine grinding had the highest EUC value and the best antioxidant capacity after HHP treatment, which might be suitable for the further processing of Morchella esculenta.

To evaluate the storage stability and flavor changes of marinated pork treated with chili and pepper essential oils, the contents of total sulfhydryl, malondialdehyde, total volatile base nitrogen (TVBN), Ca2+ATPase activity, and total viable counts of marinated pork were determined. Further, the non-volatile (umami, numb, and spicy) and volatile flavor compounds of marinated pork were analyzed. Based on the results, the chili and pepper essential oils had limited effects on the storage stability of marinated pork. However, these essential oils could inhibit the oxidation of lipids and proteins and reduce the number of microorganisms and TVBN in marinated pork within 6 days. The non-volatile flavors of the marinated pork decreased as the refrigeration time increased. It was concluded that the decomposition of umami-enhancing nucleotides (GMP, IMP, XMP), the number of flavor substances (hydroxyl-α-sanshool, hydroxyl-β-sanshool), and spicy (capsaicin) tasting compounds caused the decrease in non-volatile flavors.

Background/Aims: Taste perception is one of the most important primary oral reinforcers, driving nutrient and energy intake as well as toxin avoidance. Taste receptors in the gastrointestinal tract might as well impact appetitive or aversive behavior and thus influence learning tasks and a close relation of neural taste processing and working memory networks seems plausible. Methods: In the present pilot study, we determined the effects of five taste qualities “bitter” (quinine), “sweet” (glucose), “sour” (citric acid), “salty” (NaCl) and “umami” (monosodium glutamate, MSG) on working memory processing using functional MRI and their effect on plasma insulin and glucose levels. On six separate occasions, subjects received one of the following test substances dissolved in 200 mL tap water via a nasogastric tube (to circumvent the oral cavity): 1) 2g citric acid corresponding to 52 mM, 2) 2g NaCl; 171 mM, 3) 0.017g quinine; 0.26 mM, 4) 1g monosodium glutamate; 30 mM, 5) 25g glucose; 694 mM and 6) 200 mL tap water (placebo). Results: The taste qualities “bitter” and “umami” significantly altered brain activation patterns in the primary gustatory cortex as well as in subcortical structures, previously reported to be involved in emotional learning and memory. In contrast, glucose did not reveal any statistically significant brain activation difference. Working memory performance was not different over the six treatments. Plasma insulin and glucose levels were not affected by the different taste substances (MSG, quinine, NaCl and citric acid). Conclusions: in this pilot trial, we demonstrate that acute intragastric administration of different taste substances does not affect working memory performance in humans. However, “umami” and “bitter” have effects on brain areas involved in neural working memory, overpowering the effects of “sweet”, “salty” and “sour” reception.

Pigs show an innate preference for umami (monosodium glutamate, MSG) taste. Nevertheless, the influence of a pre and postnatal umami exposure remains unclear. An experiment was conducted to test the hypothesis that MSG inclusion into maternal diets would modify the feeding behavior of post-weaning pigs. A total of 22 sows were selected on day 85 of gestation and randomly assigned to one of two gestating and lactating programs (standard commercial diets without or with 50 g/kg of MSG). Later, 208 pigs born from these sows were selected to evaluate their preference thresholds, sensory-motivated intake, total consumption, and consumption patterns for MSG and sucrose solutions. Pigs born from MSG-fed sows showed lower (p < 0.045) preference thresholds for MSG and sucrose than did animals born from control sows, and displayed an increased (p < 0.050) sensory-motivated intake for sucrose and decreased for MSG. Conversely, no differences (p > 0.05) were observed in the total consumption or consumption patterns of MSG or sucrose solutions among pigs born from control and MSG-fed sows. It is concluded that the feeding behavior of nursery pigs can be influenced by pre and postnatal inclusion of a taste active compound into maternal diets. It would appear that a compensatory mechanism to balance dietary nutrients might be in place.

El ácido glutámico como tal o en su forma ionizada L-glutamato (GLU) es uno de los aminoácidos más abundantes en la naturaleza debido a que cumple funciones importantes a nivel celular y sistémico. En el intestino y el hígado, por ejemplo, el GLU constituye fuente de energía y es precursor de moléculas de relevancia biológica. Mientras que en el sistema nervioso central de los mamíferos actúa como neurotransmisor excitatorio, debido a la interacción con receptores específicos distribuidos en el cerebro. Además al GLU se le ha relacionado con la potenciación a corto y largo plazo de la memoria y el aprendizaje. Por otro lado, el consumo de GLU o de su sal monosódica (GMS) como aditivo alimentario genera el gusto umami, palabra japonesa que significa sabroso. El consumo de GMS ha sido considerado seguro por diferentes organizaciones que evalúan la inocuidad de uso de los aditivos alimentarios, razón por la cual han establecido una ingesta diaria admisible (IDA) "no especificada" y lo clasifican como un ingrediente reconocido como seguro o sustancia GRAS (por sus siglas en inglés, Generally Recognized Safe Substance). En esta revisión se presentan los aspectos del metabolismo del GLU, su papel en la degustación de los alimentos y la inocuidad del uso del GMS.