Pistachio Powder Research Articles

Matrix Effect of Pistachio Powder on the Quality Characteristics and Oxidation Stability of Deep-Fried Doughnuts

Matrix Effect of Pistachio Powder on the Quality Characteristics and Oxidation Stability of Deep-Fried Doughnuts

Adsorption studies of Cibacron Blue onto both untreated and chemically treated pistachio shell powder from aqueous solutions

ABSTRACT In order to enhance its adsorption properties, pistachio shell powder was modified first with aqueous HCl solution and then with aqueous NaOH solution. The adsorption of Cibacron Blue dye onto both untreated and chemically treated pistachio shell powder was investigated using a batch adsorption technique. The parameters affecting the adsorption process, namely contact time, pH, adsorbent dose, and initial dye concentration were examined. For both adsorbents, the dye adsorption was favored under acidic conditions (pH 2–3). Equilibrium adsorption isotherm and kinetic studies showed that Langmuir isotherm and the pseudo-second-order kinetic model fitted well to the experimental data.

Evaluation of the Fermentation Dynamics of Commercial Baker’s Yeast in Presence of Pistachio Powder to Produce Lysine-Enriched Breads

The present work was carried out to evaluate the microbiological, physicochemical, and sensory characteristics of fortified pistachio breads. Pistachio powder (5% w/w) was added to flour or semolina and fermented by a commercial baker’s yeast (Saccharomyces cerevisiae). Pistachio powder did not influence the biological leavening of the doughs. The kinetics of pH and total titratable acidity (TTA) during dough fermentation showed that the leavening process occurred similarly for all trials. The concentration of yeasts increased during fermentation and reached levels of 108 CFU/g after 2 h. Pistachio powder decreased the height and softness of the final breads and increased cell density of the central slices. The amount of lysine after baking increased in pistachio breads and this effect was stronger for semolina rather than flour trials. Sensory evaluation indicated that fortified breads processed from semolina were those more appreciated by the judges. This work clearly indicated that the addition of pistachio powder in bread production represents a promising strategy to increase the availability of lysine in cereal-based fermented products.

Persistence of a mixed lactic acid bacterial starter culture during lysine fortification of sourdough breads by addition of pistachio powder

Pistachio powder was added to flour or semolina to evaluate its contribution to increase the amount of lysine in bread. Bread production was carried out by sourdough technology using a selected 3-species (Lactobacillus sanfranciscensis/Leuconostoc citreum/Weissella cibaria) lactic acid bacterial (LAB) starter culture. All sourdoughs were subjected to a long-time fermentation (21 h) and showed levels of LAB around 109 CFU/g, indicating the suitability of pistachio powder for lactic fermentation. Yeasts were also detected, in particular in semolina trials. MiSeq Illumina technology was applied to investigate the bacterial composition of sourdoughs evidencing a different distribution of LAB species among the trials with Lactobacillus as major LAB group in almost all sourdoughs. Physicochemical parameters were comparable among the trials. After baking, pistachio powder was found not to influence the height of the breads, but pistachio breads were more firm than control breads. Color of the breads, void fraction and cell density, were influenced by pistachio powder. The amount of lysine increased consistently thanks to pistachio supplementation which also determined a higher presence of o-xylene, p-cymene and limonene and the appearance of α-pinene and 1-octen-3-ol in breads. Sensory tests showed the best appreciation scores for the breads produced with flour and pistachio powder.

Lipid Oxidation Kinetics of Pistachio Powder During Different Storage Conditions

AbstractThe effects of storage temperatures (15, 25, 35, and 40°C) and relative humidity (11, 33, 73 and 87%) on peroxide value, lipid oxidation and shelf life of stored pistachio powder studied in this project. Results showed that the changes in lipid oxidation follow zero‐order reaction kinetic. Additionally, the highest inhibition (or activation) energy (Ea) for oxidation of fatty acid molecules and forming hydro‐peroxides reached to ∼50 kJ/mol at relative humidity of 33%, which corresponds to monolayer moisture content of pistachio powder. Thermodynamic analysis of these reactions indicated that these reactions are endothermic (ΔH++ > 0) and nonspontaneous (ΔG++ > 0) processes.Practical ApplicationsPistachio nut (Pistachia vera L.) is one of the most popular nuts in the world with its high nutritional value and unique flavor as a snack and a food ingredient (as powder or kernel). It is also used as a main part of many traditional Persian foods such as Gaz, Baghlava and Ghotab. Fat oxidation is one of the main factors for quality loss in pistachio, i.e., changes in nutritional and organoleptic properties of this product during storage period. The main object of this research is the kinetic effects of different storage temperature and RH on auto‐oxidation of pistachio powder's lipid during storage period. Generally, the results are applicable by pistachio powder's workstations and their producing factories during processing and storage for controlling the shelf life.

New approach to the calculation of pistachio powder hysteresis

Abstract Moisture sorption isotherms for pistachio powder were determined by gravimetric method at temperatures of 15, 25, 35 and 40°C. A selected mathematical models were tested to determine the best suitable model to predict isotherm curve. The results show that Caurie model had the most satisfactory goodness of fit. Also, another purpose of this research was to introduce a new methodology to determine the amount of hysteresis at different temperatures by using best predictive model of isotherm curve based on definite integration method. The results demonstrated that maximum hysteresis is related to the multi-layer water (in the range of water activity 0.2-0.6) which corresponds to the capillary condensation region and this phenomenon decreases with increasing temperature.

Estimation of Equilibrium Moisture Content of Pistachio Powder through the ANN and GA Approaches

Abstract In this study, two intelligent tools of genetic algorithm (GA) and artificial neural network (ANN) were employed to use experimental data to predict equilibrium moisture content (EMC) of Persian pistachio powder. Initially the moisture sorption isotherms of pistachio powder were determined by gravimetric method at different temperatures (15, 25, 35 and 40°C) and constant relative humidity’s (0.11, 0.23, 0.36, 0.49, 0.62, 0.75 and 0.88 aw values) and then traditional mathematical models including BET, Iglesias and Chirife, GAB, Caurie and Freundlich were used to check the fitness of experimental data. Later the experimental data were compared with similar data obtained from GA and ANN models. The overall results showed that the Caurie model had high performance to predict EMC and revealed that GA model had greater accuracy to predict EMC of pistachio powder with very high R 2 values (equal to 0.9996).

APPLICATION OF NEURAL NETWORK FOR ESTIMATION OF PISTACHIO POWDER SORPTION ISOTHERMS

Moisture sorption isotherms for pistachio powder were determined by gravimetric method at temperatures of 15, 25, 35 and 40ºC. Some mathematical models were tested to measure the amount of fitness of experimental data. The mathematical analysis proved that Caurie model was the most appropriate one. As well, adsorptiondesorption moisture content of pistachio powder were predicted using artificial neural network (ANN) approach. The results showed that, MLP network was able to predict adsorption-desorption moisture content with R2 values of 0.998 and 0.992, respectively. Comparison of ANN results with classical sorption isotherm models revealed that ANN modeling had greater accuracy in predicting equilibrium moisture content of pistachio powder.

ESTIMATION OF MOISTURE SORPTION ISOTHERMS IN KERMAN PISTACHIO NUTS

ABSTRACT Various postharvesting processes such as handling, drying, storing and transportation of pistachio nuts are affected by their equilibrium moisture content (EMC). The static gravimetric method, along with different saturated salt solutions, was used in a range of water activity of 0.11–0.88, and at 15, 25, 35 and 40C to obtain sorption isotherms of pistachio nuts. Each set of sorption data was fitted to six mathematical equations, including Brunauer, Emmett and Teller; Guggenheim, Anderson and De Boer; Smith; Oswin; Halsey; and Henderson. The Smith model gave the most appropriate results (fitness) over the entire range of the mentioned temperatures. The isosteric sorption heats were determined for adsorption and desorption of pistachio nuts using the relevant thermodynamic relations (i.e., Clausius–Clapeyron equation). Based on experimental sorption data, a noticeable hysteresis effect between adsorption and desorption processes was observed, and their EMC plots were significantly deviated and different from each other. PRACTICAL APPLICATIONSThe rehydration rate of pistachio kernels and powder when they are mixed with various ice creams, desserts and confectionary products depends mainly on their sizes, temperature, and water activity. These factors have considerable effects on texture properties and release of flavor of pistachio's final products. To enhance the organoleptic properties of the above‐mentioned products, it is important to choose proper sizes of pistachio kernels. Since hysteresis and binding energy of pistachio powder are less than those of pistachio kernels, especially at 15°C, its rehydration rate is faster, and therefore it releases more flavor to the product (water activity in the range of 0.2–0.7) than pistachio kernels. However, the crunchy taste in pistachio powder is less than that in pistachio kernels. Overall, more research is needed to choose proper sizes of pistachio kernels for mixing with different products (such as ice cream) to keep their high crispness and maximize their flavor‐releasing process during rehydration, and also to use minimum energy for cooling and freezing.

Moisture sorption isotherms and isosteric heat for pistachio

The equilibrium moisture contents (EMC) of pistachio were determined using the standard static-gravimetric method at 15, 25, 35 and 40 °C for pistachio powder at 15, 35 °C for pistachio kernel and pistachio nut for water activity (aw) ranging from 0.11 to 0.9. At a given water activity, the results show that the moisture content decreases with increasing temperature. The experimental sorption curves are then described by the BET, GAB, Henderson, Oswin, Smith and Halsey models. A nonlinear regression analysis method was used to evaluate the constants of the sorption equations. The Smith model was found to be suitable for describing the sorption curves. The isosteric heat of adsorption of water was determined as a function of moisture content from the equilibrium data at different temperatures using the Clasius–Clapeyron equation.