Effects Of Storage Relative Humidity Research Articles

Effect of storage relative humidity on the survival kinetics of salmonella spp., in different tree nut flours

This study determined the effect of relative humidity (RH) on the survival kinetics of Salmonella enterica in tree nut flours during long term storage. Three types of tree nut (almond, chestnut, and hazelnut) flours were seed inoculated with Salmonella (3-strain) to achieve about 8 log CFU/g and stored at different RH (25, 45 and 70%) conditions under ambient temperature (21 ± 2 °C) storage for up to 120 days. Samples were analyzed at regular intervals (0, 7, 14, 21, 30, 60, 90, and 120 days) to determine the survivors on both selective and non-selective media. Salmonella populations were declined by 2.28–4.68 log CFU/g on the tested flours during the storage period. Compared to RH 25%, 70% showed a significant (P ≤ 0.05) decrease in Salmonella survival. Type of flour was found to have a variable effect on the survival of Salmonella. After 120 days of storage at 70% RH, reductions were higher on hazelnut followed by almond and chestnut flours, respectively. Bacterial population decline was found to be higher during the first 60 days of storage at 25 and 45% RH. At the same time, cell viability decreased most between 60 and 120 d in hazelnut and almond flour at 70% RH.

Effect of relative humidity, initial seed moisture content and storage container on soybean (Glycine max L. Meril.) seed quality

To find out the effect of storage relative humidity, seed moisture content and type of storage container on soybean seed quality, an experiment was conducted at the Seed Laboratory, Department of Agronomy, Bangladesh Agricultural University Mymensingh in 2008 and 2009. In 2008, soybean seed has 96% initial germination and in 2009 seed having 98% initial germination was stored at 8% and 12% initial moisture levels in two types of storage containers viz., cloth bag and polythene bag (0.06mm thickness). The final seed moisture content, germination percentage, germination index, and seedling dry matter of the seed under different treatments were measured at 60,120, and 180 days after storage (DAS). The experiment was arranged in a completely randomized design with three replications. In 2008, highest germination percentage (89.33%) of soybean seed was retained at 180 days after storage (DAS) for those stored at 8% initial seed moisture content (SMC) in polythene bag at 50% relative humidity. Germination index and seedling dry matter decreased with increased initial seed moisture content irrespective of storage containers used. In 2009, highest germination percentage (92.67%) of soybean seed was retained at 180 DAS for those stored in polythene bag at 8% initial SMC at 50% of the relative humidity. Those stored in cloth bag at 12% SMC showed rapid germination loss and the value went down to 0.00 in both the years. Vigour index and seedling dry matter decreased with increased initial seed moisture content irrespective of storage containers used. DOI: http://dx.doi.org/10.3329/bjar.v39i3.21989 Bangladesh J. Agril. Res. 39(3): 461-469, September 2014

Effect of Storage Relative Humidity on Some Chemical Composition and Browning Development of Treated Cocoyam (Colocasia esculenta) Corm Flour

Effect of Storage Relative Humidity on Some Chemical Composition and Browning Development of Treated Cocoyam (Colocasia esculenta) Corm Flour

Effect of Storage Relative Humidity on Physical Stability of Dried Fig

The objective of this study was to assess the effect of storage condition (relative humidity) on the structural stability of dried fig. Moisture sorption isotherms of dried fig were obtained at 5, 25 and 40C. Dried fig, like most high-sugar content materials, showed a type I isotherm and the sorption capacity of the sample decreased with increasing the temperature. The glass transition temperature (T g) and the melting enthalpy (ΔH m) of dried figs equilibrated at different relative humidities were measured using differential scanning calorimetry (DSC). The percentage of crystallization was measured using wide angle X-ray diffraction (WAXD). It was revealed that the extent of sugar crystallization increased at the intermediate relative humidity region, as implied by WAXD. The same result was observed by measuring ΔH m using DSC. The impact of different relative humidities on the sugar crystallization was explained in terms of (T − T g). Practical Applications Fig is mostly used in dried form. Low molecular weight sugars are the major component of fig solid. The physical states of these sugars play an important role in stability of dried fig during storage. Changes in water content as a function of storage condition may lead to undesired physical properties in dried fig which is of great importance for its structure and quality. Water has a great plasticization effect on this fruit and distresses its T g. Crystallization of amorphous sugars is the most important issue for physical instability of dried fig and other dried fruits with high-sugar contents during storage. The rate and extent of this phenomenon increase at intermediate relative humidities and can be described in term of T − T g. The present results showed that intermediate storage relative humidities are critical for the physical stability of dried fig during storage.

Development of an integrated approach for the stability testing of flavonoids and ascorbic acid in powders

An integrated approach for determining the stability of flavonoids and ascorbic acid in powders was developed. A rapid analyte solubility procedure was used to decide whether HPLC, GLC, or NMR would best serve to measure the stability of each flavonoid. Both the flavonoid under study and ascorbic acid were measured in one analysis with any of the determinative methods. Seventeen flavonoids of differing types, as well as ascorbic acid, were evaluated to establish the approach. The effects of storage relative humidity (RH) on the stability of several flavonoid powders with and without ascorbic acid were then determined. Quercetin, luteolin, taxifolin, naringenin, and naringin were stable for up to 8 weeks in RHs up to 98%, and ascorbic acid was significantly destroyed in the presence of quercetin, luteolin, and taxifolin at 98% RH. Both grape anthocyanins and ascorbic acid were unstable in the presence of each other at 98% RH. The integrated approach could be used for shelf-life testing of powdered flavonoids under a variety of storage conditions.

Impact of Deliquescence on the Chemical Stability of Vitamins B1, B6, and C in Powder Blends

Single vitamin ingredients and blends in premixes are widely used in the food and supplement industries and are predominantly in powder form. To meet label claims and/or determine appropriate overages, it is important to characterize the stability of these ingredients. Although moisture is a known promoter of instability in powder blends, the combined effects of storage relative humidity (RH), formulation, and deliquescence on the stability of these systems are not well-characterized. The objective of this study was to determine the effect of deliquescence on the stability of vitamins B 1, B 6, and C and their mixtures. Deliquescence points (RH 0s) for all formulations were determined by moisture sorption analysis. Single, binary, ternary, and quaternary mixtures of thiamin HCl, pyridoxine HCl, sodium ascorbate, and fructose were stored in RH-controlled environmental chambers between 43 and 98% RH at 22 degrees C for up to 12 weeks. Vitamin stability was determined by high-performance liquid chromatography (HPLC). Formulation and storage RH significantly affected vitamin stability. Thiamin and ascorbate degradation were significantly promoted above the RH 0, while pyridoxine was least affected by storage RH. The deliquescence lowering phenomenon enhanced moisture sorption of blends at RHs below the RH 0s. Ascorbate enhanced thiamin degradation. Therefore, formulation, storage conditions, and the relation of these to deliquescence points may affect the shelf life, quality, and functionality of vitamin blends and should be considered in product development, processing, storage, and use.

Interaction of Environmental Moisture with Powdered Green Tea Formulations: Effect on Catechin Chemical Stability

Green tea and tea catechins must be stable in finished products to deliver health benefits; however, they may be adversely affected by tea processing/storage conditions and the presence of other components. The objective of this study was to determine the effects of storage relative humidity (RH) and addition of other ingredients on catechin stability in simulated dry beverage mixtures. Samples of green tea powder alone and mixed with sucrose, citric acid, and/or ascorbic acid were prepared and stored in desiccators at 22 degrees C and 0-85% RH for up to 3 months. Epicatechin, epigallocatechin, epicatechin gallate, and epigallocatechin gallate were determined by high-performance liquid chromatography (HPLC). Formulation and the interaction of formulation and RH significantly promoted catechin degradation ( P < 0.0001). The chemical degradation of total and individual catechins in green tea powder formulations was significantly increased ( P < 0.0001) by exposure to increasing RH, and the degradation was exacerbated at > or = 58% RH by the presence of powdered citric acid and at > or = 75% RH by the presence of ascorbic acid. Catechins degraded the most in formulations containing both acids. Although catechin chemical stability was maintained at < or = 43% RH in all samples stored at 22 degrees C for 3 months, caking was observed in samples at these relative humidities. These results are the first to demonstrate that addition of other dry components to tea powders may affect catechin stability in finished dry blends and highlight the importance of considering the complex interplay between a multicomponent system and its environment for developing stable products.

Effect of storage relative humidity on germination and vigour of wheat seed

Effect of storage relative humidity on germination and vigour of wheat seed

The effect of moisture sorption on electrostatic charging of selected pharmaceutical excipient powders

An experimental investigation has been undertaken to determine the effects of moisture sorption propensity on the triboelectrification of pharmaceutical excipients in contact with materials used for the fabrication of pharmaceutical processing equipment and drug delivery devices. Moisture sorption and desorption isotherms were determined for α-lactose monohydrate, dextrose monohydrate, spray-dried sorbitol and sodium starch glycolate. The isotherms show that α-lactose monohydrate and dextrose monohydrate are non-hygroscopic over a wide range of relative humidity (rh) from 0% to 80% and have negligible hysteresis on desorption. Sodium starch glycolate was the most hygroscopic, spray-dried sorbitol was of intermediate hygroscospicity and both isotherms showed hysteresis on desorption. The sorption data was analysed to estimate the distribution of monolayer adsorbed, multilayer adsorbed and absorbed moisture. The effect of storage relative humidity on the triboelectrification of the powders was investigated using steel, polypropylene and polyvinylchloride (PVC) as contact surfaces. The results showed that moisture sorption and distribution data could be useful in predicting the electrostatic charging of pharmaceutical powders. There was negligible effect of rh on the charging of the excipients with low hygroscopicity, whereas the charging of the sodium starch glycolate was inversely related to the storage rh. The relationship between moisture sorption/distribution and electrostatic charging for spray-dried sorbitol was more complex and attributed to the greater distribution of sorbed water in the pore structure of the sorbitol. The non-hygroscopic excipients charged negatively with steel and positively with PVC and polypropylene, whereas sodium starch glycolate charged negatively with all contact surfaces.

The Effect of Storage Relative Humidity and Initial Moisture Content on the Staling and Associated Textural Changes of Layer Cakes

The Effect of Storage Relative Humidity and Initial Moisture Content on the Staling and Associated Textural Changes of Layer Cakes

The Effect of Storage Relative Humidity on Calcium Uptake by ‘Spartan’ Apple1

Abstract Low relative humidity (73%–80%) and high relative humidity (94%) lowered the initial rate of calcium penetration from postharvest dip into the tissues of ‘Spartan’ apple fruits (Malus domestica Borkh.). Moderate storage relative humidity (87%) resulted in the most rapid initial uptake of calcium by the tissues. The effect of humidity on calcium movement into the fruit tissue decreased with time in storage.