Compendium of the most significant studies with reference to properties, intake, effects.

EFSA Panel on Food additives and Nutrient Sources added to Food (ANS). (2014). Scientific Opinion on the re‐evaluation of propionic acid (E 280), sodium propionate (E 281), calcium propionate (E 282) and potassium propionate (E 283) as food additives. EFSA Journal, 12(7), 3779.

Abstract. The EFSA ANS Panel provides a scientific opinion re-evaluating the safety of propionic acid (E 280), sodium propionate (E 281), calcium propionate (E 282) and potassium propionate (E 283) which are authorised as food additives in the EU and have been previously evaluated by the SCF and JECFA. JECFA allocated an ADI “not limited”. The SCF concluded that potassium propionate could be added to the list of preservatives and established an ADI ”not specified”. Propionates are naturally occurring substances in the normal diet. The Panel considered that forestomach hyperplasia reported in long-term studies in rodents is not a relevant endpoint for humans because humans lack this organ. Based on the reported presence of reversible diffuse epithelial hyperplasia in the oesophagus the LOAEL for a 90-day study in dogs was considered by the Panel to be 1 % propionic acid in the diet and the NOAEL to be 0.3 % propionic acid in the diet. The Panel considered that there is no concern with respect to genotoxicity and carcinogenicity. The Panel concluded that the present database did not allow allocation of an ADI for propionic acid - propionates. The overall mean and 95th percentile exposures to propionic acid - propionates resulting from their use as food additives (major contributor to exposure) ranged from 0.7-21.1 and 3.6-40.8 mg/kg bw/day, respectively. The Panel noted that the concentration provoking site of contact effect in the 90-day study in dogs (1 % propionic acid in the diet) is a factor of three higher than the concentration of propionic acid - propionates in food at the highest permitted level and concluded that for food as consumed, there would not be a safety concern from the maximum concentrations of propionic acid and its salts at their currently authorised uses and use levels as food additives.

Graham D, Kingdom JC, McDonald J, Davies DL, Kenyon CJ. Platelet sodium/hydrogen ion exchange in normal pregnancy and non-proteinuric pre-eclampsia. J Hum Hypertens. 1997 Jul;11(7):453-8. doi: 10.1038/sj.jhh.1000474. 

Abstract. In non-pregnant individuals, abnormalities in cation transport in vascular tissues have been linked to essential hypertension. In the present study, we consider whether Na+/H+ exchange (NHE) is affected in non-proteinuric pre-eclampsia (NPP). Platelet NHE characteristics and plasma cholesterol were measured in a cross-sectional study of normal primigravidae at 14 +/- 0.5 (n = 9), 29 +/- 0.7 (n = 7), 39 +/- 0.4 (n = 8) weeks gestation, in women with NPP (n = 15) and in non-pregnant women (n = 8). Amiloride-sensitive 22Na uptake was measured in platelets which had been acid loaded, to stimulate NHE, by suspension in isotonic potassium propionate buffer (pH 6.7). Intraplatelet radioactivity was used to calculate the affinity (Km) and the capacity (Vmax) of Na+ uptake. In normotensive women, Vmax (mean +/- s.e.) at 14, 29, 39 weeks gestation and 6 weeks postpartum were 452 +/- 46, 469 +/- 33, 713 +/- 101 and 562 +/- 77 pmolNa+/10(6) cells/min respectively; the third trimester values were higher (P < 0.05) than those in the first and second trimester and were also higher than those of non-pregnant women (415 +/- 20). Vmax of patients with NPP in the third trimester (712 +/- 44) was not different from gestational age-matched controls. Km values were not affected by gestational age or NPP. Plasma cholesterol concentration was positively correlated with Vmax values during normotensive pregnancy (r = 0.493, P < 0.05). In conclusion, the capacity for amiloride-sensitive Na+ uptake by platelets correlates positively with gestational age during normal pregnancy. However, neither the capacity nor affinity for Na+ was altered in NPP platelets suggesting that NHE is not implicated in the pathophysiology of this condition.

Hansen, L. J., & Westover, M. B. (1970). Application of a powdered antifungal substance to the surfaces of intact or cut cheese.  (1 492 761).

Abstract. A dry, pulverized substance, e.g. sorbic acid or its salts, metal salts of propionic acid, e.g. sodium or potassium propionate, is applied to all surfaces of cheese by compressed air. A pressure, preferably of 0.7-1.4 kg/cm2, ensures good adhesion of the substance to the cheese. W&Co

Mirnaya, T. A., Yaremchuk, G. G., & Volkov, S. V. (1994). Phase states of binary systems of sodium, potassium and cesium propionates. Theoretical and Experimental Chemistry, 30, 73-77.

Abstract. Differential thermal analysis and hot-stage polarization microscopy were used to study the phase diagrams of binary systems of sodium, potassium, and cesium propionates. The induction of type-A smectic liquid crystals was observed in the sodium-containing systems. Liquid crystal formation in systems composed of components, which are individually nonmesomorphic, is attributed to latent mesomorphism of sodium propionate or potassium propionate.

Bohr, D. F., & Webb, R. C. (1988). Vascular smooth muscle membrane in hypertension. Annual review of pharmacology and toxicology, 28(1), 389-409.

Abstract....How can we understand a role of the organic salts as well as a role of the SSI? KC1 acts less effectively than potassium acetate, while potassium propionate is as effective as potassium acetate. The bulky moieties of organic anions may have exerted an action to separate ionic interactions existing at the outer surface of the protein structure, thus inducing a strong hydrophobic core structure of the protein to fold easily. A study on the accelerating effect of SSI as template for Sbtl refolding, if any, is underway by use of a reversible unfolding/refolding system of an immobilized Sbtl preparation (Hayashi et al., 1993).