1. An optimized organic acid human sensory sourness analysis method
Yuezhong Mao, Shiyi Tian, Yumei Qin, Shiwen Cheng J Sci Food Agric. 2021 Nov;101(14):5880-5887. doi: 10.1002/jsfa.11240. Epub 2021 Apr 23.
Background: Sour taste perception builds on both chemical and physiological foundations, and plays an important role in food flavor, including that of fruit, beer, wine, and other beverages. A uniform sourness standard and sourness conversion method for researchers and food enterprises is necessary to obtain uniform conclusions. Results: This study established an optimized organic acid sensory sourness analysis and sourness conversion method. It is based on sour sensory difference strength curves, which consist of an absolute threshold value and sensory difference threshold values. Defining the absolute threshold value of citric acid sourness as 1, sourness could be calculated according to the curve. With a logarithmic curve form, the acid sourness indexes (AI) were calculated as 1, 0.74, 0.77, 1.31, and 1.21 for citric, malic, fumaric, lactic, and tartaric acid samples, respectively. Consequently, each acid's sourness and concentration could be obtained and converted. Single acid and mixed acid sourness comparison evaluation's result implied that the novel method was more accurate (91.7-100%) than the hydrogen ion concentration method. Conclusion: The novel sourness determination and conversion equation would provide more accurate sourness standard and calculation method in food sensory areas. © 2021 Society of Chemical Industry.
2. The Stephan Curve revisited
William H Bowen Odontology. 2013 Jan;101(1):2-8. doi: 10.1007/s10266-012-0092-z. Epub 2012 Dec 6.
The Stephan Curve has played a dominant role in caries research over the past several decades. What is so remarkable about the Stephan Curve is the plethora of interactions it illustrates and yet acid production remains the dominant focus. Using sophisticated technology, it is possible to measure pH changes in plaque; however, these observations may carry a false sense of accuracy. Recent observations have shown that there may be multiple pH values within the plaque matrix, thus emphasizing the importance of the milieu within which acid is formed. Although acid production is indeed the immediate proximate cause of tooth dissolution, the influence of alkali production within plaque has received relative scant attention. Excessive reliance on Stephan Curve leads to describing foods as "safe" if they do not lower the pH below the so-called "critical pH" at which point it is postulated enamel dissolves. Acid production is just one of many biological processes that occur within plaque when exposed to sugar. Exploration of methods to enhance alkali production could produce rich research dividends.
3. Dietary Acid Load Associated with Hypertension and Diabetes in the Elderly
Tulay Omma, Nese Ersoz Gulcelik, Fatmanur Humeyra Zengin, Irfan Karahan, Cavit Culha Curr Aging Sci. 2022 Aug 4;15(3):242-251. doi: 10.2174/1874609815666220328123744.
Background: Diet can affect the body's acid-base balance due to its content of acid or base precursors. There is conflicting evidence for the role of metabolic acidosis in the development of cardiometabolic disorders, hypertension (HT), and insulin resistance (IR). Objective: We hypothesized that dietary acid load (DAL) is associated with adverse metabolic risk factors and aimed to investigate this in the elderly. Methods: A total of 114 elderly participants were included in the study. The participants were divided into four groups, such as HT, diabetes (DM), both HT and DM, and healthy controls. Anthropometric, biochemical, and clinical findings were recorded. Potential renal acid load (PRAL) and net endogenous acid production (NEAP) results were obtained for three days, 24-hour dietary records via a nutrient database program (BeBiS software program). Results: The groups were matched for age, gender, and BMI. There was a statistically significant difference between the groups regarding NEAP (p =0.01) and no significant difference for PRAL ( p = 0.086). The lowest NEAP and PRAL levels were seen in the control group while the highest in the HT group. Both NEAP and PRAL were correlated with waist circumference (r = 0,325, p = 0.001; r=0,231, p =0,016, respectively). Conclusion: Our data confirmed that subjects with HT and DM had diets with greater acid-forming potential. High NEAP may be a risk factor for chronic metabolic diseases, particularly HT. PRAL could not be shown as a significantly different marker in all participants. Dietary content has a significant contribution to the reduction of cardiovascular risk factors, such as HT, DM, and obesity.
