Increase in Umami through Cooking
Umami substances are naturally present in various ingredients, such as certain proteins, aged cheeses, mushrooms, and fermented products. However, it is important to note that the sources of umami are not solely limited to these base ingredients. Throughout the process of cooking, there are different transformations and reactions that take place, which can result in the generation and intensification of umami flavors.
Cooking involves various techniques such as heating, roasting, fermenting, and aging, which can significantly impact the taste profile of food. These processes can cause chemical changes in the ingredients, leading to the formation of new compounds and the breakdown of others. As a result, umami substances may be created, released, or enhanced during cooking, even in ingredients that may not have exhibited strong umami properties in their raw state.
For example, the Maillard reaction, which occurs when proteins and carbohydrates are heated together, can produce flavorful compounds that contribute to umami taste. This reaction is responsible for the browning and savory aromas in seared meat, roasted vegetables, and toasted bread. Similarly, fermentation processes, such as those involved in the production of soy sauce or miso paste, can generate high levels of umami through the action of microorganisms breaking down proteins and carbohydrates.
Literature to Explore
This topic has been studied by scientists over the world throughout past decades. Here are a few examples
Concentration of Umami Compounds in Pork Meat and Cooking Juice with Different Cooking Times and Temperatures
Minna K Rotola-Pukkila, Seija T Pihlajaviita, Mika T Kaimainen, Anu I Hopia
This study examined the concentrations of umami compounds, including both amino acids and nucleic acids, in pork loins cooked at different temperatures and different lengths of cooking times. Their primary observation was the impact of cooking temperature on the amino acid concentrations found in the juice (note: not the meat) released from meat. When meat was cooked at 80 °C (176 °F) compared to 60 °C (140 °F) and 70 °C (158 °F,) higher levels of amino acids were detected. This can be attributed to the breakdown of proteins and peptides induced by heat, leading to the release of water-soluble free amino acids (FAAs) into the cooking juice. The study found that cooking time and temperature had no effect on the concentrations of inosinic acid (IMP,) a nucleotide. However, adenosine monophosphate (AMP) concentrations increased with higher temperatures and longer cooking times. This suggests that the selection of time and temperature in sous vide cooking has an impact on the nucleotide concentration in pork meat.
Rotola‐Pukkila, M. K., Pihlajaviita, S. T., Kaimainen, M. T., & Hopia, A. I. (2015). Concentration of umami compounds in pork meat and cooking juice with different cooking times and temperatures. Journal of Food Science, 80(12), C2711-C2716.
Identification of Umami Taste in Sous-Vide Beef by Chemical Analyses, Equivalent Umami Concentration, and Electronic Tongue System
Young-Hwa Hwang, Ishamri Ismail, Seon-Tea Joo
The study examines umami substances in beef eye of round cooked in different temperatures and different durations, aiming to test the ability of the electronic tongue system (INSENT SA402B.)
They found a decrease in inosinic acid (IMP) content during cooking; the control sample showed a minimum 6% reduction in IMP after 30 minutes of cooking, with sous-vide samples experiencing larger reductions after prolonged cooking of 6–12 hours at 60/70 °C (140–158 °F.) The degradation of IMP is influenced significantly by temperature and can be attributed to two possible mechanisms: (i) dephosphorylation of IMP into inosine, or (ii) the involvement of IMP and ribose as flavor precursors, which undergo various secondary reactions resulting in the formation of volatile compounds with heterocyclic structures. The specific reaction pathway depends on the temperature applied; notably, the lower IMP values at 60 °C and higher values at 70 °C may be explained by enzymatic activity as observed as higher proteolytic activity at 60 °C compared to 70 °C. Ishiwatari et al found that enzyme activity decreased when meat was heated above 60 °C, and complete deactivation of the IMP-decomposition enzyme activity was achieved at 64.1 °C (147.4 °F.) The study did not find significant differences in amino acids between different temperatures and cooking times.
Hwang, Y. H., Ismail, I., & Joo, S. T. (2020). Identification of umami taste in sous-vide beef by chemical analyses, equivalent umami concentration, and electronic tongue system. Foods, 9(3), 251.
Decomposition of Inosinic Acid in Flesh during Cooking
Kazuko Tomioka, Seunah Yang, Kinji Endo
This study examined the change in amount of IMP in beef, pork, chicken, and 11 different fish meat in rapid and slow cooking methods, at increase of temperature at 7.5 °C (13.5 °F)/minute and 0.8 °C (1.44 °F)/minute respectively. They found that IMP is decomposed more when the meat is heated slowly, and the extent varies among different meats; it was discussed that when the meat was cooked in slow heating, it was exposed to the temperature where the enzymes like 5'-nucleotidase and acid phosphatase are active and decompose inosinic acid for a longer time period. Enzyme denaturation temperature was below 65 °C (149 °F) and those enzymes were deactivated before reaching that temperature. The threshold temperatures varied and the differences in the threshold might affect the IMP decomposition rates in different kind of meats.
Tomioka, K., Yang, S., & Endo, K. (1993). Decomposition of inosinic acid in flesh during cooking. Journal of Home Economics of Japan, 44(1), 11–16.
Changes in the Taste and Taste Components of Beef during Heating at a Low Temperature for a Long Time
Katsue Ishii, Mitose Tsuchida, Toshihide Nishimura, Akihiro Okitani, Atsuko Nakagawa, Keiko Hatae, Atsuko Shimada
The study focused on understanding the changes in taste and taste components of beef when subjected to low-temperature heating for extended periods. Thin slices of beef loin were vacuum-packed and heated at temperatures of 40, 60, and 80 °C (104, 140, and 176 °F) for durations of 10, 60, 180, and 360 minutes. The analysis revealed that the largest increase in free amino acids occurred in the sample heated at 40°C for 360 minutes due to the the action of the aminopeptidases in muscle, while the sample heated at 60 °C for 360 minutes showed the greatest increase in acid-soluble peptides. A sensory evaluation was conducted, and it was found that the extract derived from beef heated at 60 °C for 360 minutes exhibited a milder taste compared to the extract from beef heated at 60°C for 10 minutes. Although both extracts had similar levels of free amino acids and 5'-IMP, the enhanced mildness of taste in the 360-minute sample can be attributed to the increased peptide content.
Ishii, K., Tsuchida, M., Nishimura, T., Okitani, A., Nakagawa, A., Hatae, K., & Shimada, A. (1995). Changes in the taste and taste components of beef during heating at a low temperature for a long time. Journal of Home Economics of Japan, 46(3), 229–234.
Implications
Temperature and cooking durations matter for the amount of umami substances in the ingredients. Different umami substances show different reactions to cooking conditions.
It is observed that inosinic acids are preserved when the ingredients are less exposed to the temperature zone where the enzymes are active; inosinic acids are decomposed below the temperature under 60–65 °C (140–149 °F) while the threshold temperature depends on the meat variety.
Free amino acids represented by glutamic acid increase around 40 °C (104 °F) but not much at higher temperatures around 60–80 °C (140–176 °F) in meat, while proteins are degraded to water soluble free amino acids around 80 °C (176 °F) so it can be considered to cook meat around that temperature for soup or other liquid form of cuisine.
It is also noted that there are other factors that change during cooking and affect the perception of umami. For example peptides, short chains of amino acids, contribute to the perception of umami, and they increase most rapidly when cooked around 60 °C (140 °F.)
