Deliquescence Behavior and Chemical Stability of Vitamin C Forms (Ascorbic Acid, Sodium Ascorbate, and Calcium Ascorbate) and Blends

Abstract

The stability and type of vitamin C added to foods is important for enhancing product quality, label claims, and shelf-life. To improve understanding of stability, the effects of deliquescence, storage relative humidity (RH) formulation, and addition of ascorbyl palmitate and dehydroascorbic acid on degradation of vitamin C at 25 • C were studied. Individual vitamin C forms (ascorbic acid, sodium, and calcium ascorbate) and mixtures were stored below, near, and above their deliquescence RH for up to 12 weeks. Vitamin C stability was significantly affected by RH and vitamin form (p < 0.0001). Formulation affected deliquescence and chemical stability: mixtures were significantly less stable above RH 0mix than below (p < 0.0001). Ascorbyl palmitate-enhanced degradation rates of more soluble vitamin C forms, and the presence of dehydroascorbic acid reduced vitamin blend stability. It is important that vitamin C products be stored below the deliquescence RH to avoid enhanced vitamin losses.

Effect of Temperature and Initial Moisture Content on the Chemical Stability and Color Change of Various Forms of Vitamin C

“…[10] For sodium ascorbate samples, there were no significant differences in chemical stability at the different storage temperatures (22, 35, or 40 • C) or with various amounts of initial moisture determined using UV/Vis and titration techniques (data not shown). Trends in the stability of sodium ascorbate at these temperatures were similar to those found for ascorbic acid at 22 and 35 • C. The chemical degradation of ascorbic acid appeared to follow first-order reaction rate kinetics (Table 3) consistent with previous reports, [9,10] although when data were fit to zero-order kinetic models the R 2 results were similar (data not shown). The limited amount then fit to the Arrhenius equation, and results are shown in Table 4.…”

“…[22] Based upon this approach, the RH 0 of ascorbic acid is 96.8% RH at 25 • C, while the RH 0 of sodium ascorbate is 85.6% RH at 25 • C. These values are near previous reports of 98% RH for ascorbic acid and 86% RH for sodium ascorbate. [9] No differences in chemical stability were seen in sodium Downloaded by [Selcuk Universitesi] at 01:27 07 February 2015 a,b,c,d Denotes significant difference (P < 0.05) between water activities within the same form of vitamin C; * Indicates where saturation occurs, as determined using a water activity meter using four grams of sample with various amounts of water correlating to 0-5 mol water/mol solid. For solution based samples (15-50 mol water/mol solid) samples were premade in 20 mL vials, with 2 mL of solution added to the water activity meter cup; * * Denotes a w above the critical a w (RH 0 ) for sodium ascorbate and ascorbic acid.…”

“…Others have reported that at RHs below RH 0 , vitamin C is relatively stable, while above or approaching RH 0 , vitamin C begins to degrade. [9] However, in these studies, the powdered samples sorbed moisture over time while stored in open containers in constant RH desiccators, and this may have led to differences in degradation pathways and altered the moisture sorption threshold relating to chemical degradation. [9,23] A general linear ANOVA test was conducted to determine the contribution of treatment variables (storage time, storage temperature, initial moisture content, and vitamin C type) to chemical stability (Table 6).…”

“…[9,10] Hiatt et al [9] suggested that a 1 mol water/mol solid ratio was the threshold moisture content above which the chemical stability for vitamin C was reduced. Therefore, it was hypothesized that increasing amounts of initial moisture or increasing storage temperature will lead to enhanced chemical degradation over time.…”

Determination of dosimetric and kinetic features of gamma irradiated solid calcium ascorbate dihydrate using ESR spectroscopy

“…It is commonly used in food and cosmetic industries as an antioxidant (4)(5)(6)(7)(8) and in medicine as vitamin C and Ca source (9)(10)(11)(12). CaAs is a common antibrowning agent for several fresh-cut fruits, primarily for apples (13)(14)(15)(16)(17)(18)(19).…”