Pineapple Puree Research Articles

Empirical model based on Weibull distribution describing the destruction kinetics of natural microbiota in pineapple (Ananas comosus L.) puree during high-pressure processing

High pressure inactivation of natural microbiota viz. aerobic mesophiles (AM), psychrotrophs (PC), yeasts and molds (YM), total coliforms (TC) and lactic acid bacteria (LAB) in pineapple puree was studied within the experimental domain of 0.1–600MPa and 30–50°C with a treatment time up to 20min. A complete destruction of yeasts and molds was obtained at 500MPa/50°C/15min; whereas no counts were detected for TC and LAB at 300MPa/30°C/15min. A maximum of two log cycle reductions was obtained for YM during pulse pressurization at the severe process intensity of 600MPa/50°C/20min. The Weibull model clearly described the non-linearity of the survival curves during the isobaric period. The tailing effect, as confirmed by the shape parameter (β) of the survival curve, was obtained in case of YM (β<1); whereas a shouldering effect (β>1) was observed for the other microbial groups. Analogous to thermal death kinetics, the activation energy (Ea, kJ·mol−1) and the activation volume (Va, mL·mol−1) values were computed further to describe the temperature and pressure dependencies of the scale parameter (δ, min), respectively. A higher δ value was obtained for each microbe at a lower temperature and it decreased with an increase in pressure. A secondary kinetic model was developed describing the inactivation rate (k, min−1) as a function of pressure (P, MPa) and temperature (T, K) including the dependencies of Ea and Va on P and T, respectively.

Effect of combined high pressure–temperature treatments on color and nutritional quality attributes of pineapple (Ananas comosus L.) puree

Abstract High pressure processing (HPP) had a significant effect (p Industrial relevance Consumer demand for high quality pineapple puree with minimal processing explores the possibility of applying high pressure processing (HPP) as an alternative nonthermal processing to this product. On the other hand, association of moderate temperature (30–70 °C) with high pressure is necessary to inhibit the enzymatic spoilage in the product. Though HPP at moderate temperature ensures the product safety and longer shelf life, the impact on process parameters on the nutritional and other organoleptic properties of the product cannot be neglected. Detailed study on the effect of high pressure process parameters viz. pressure, temperature and treatment time on the nutritional quality attributes is needed prior to the optimization of HPP conditions. Developed RSM models to each quality attribute will quantify the changes happening during HPP combined with moderate temperatures.

Kinetic modeling of polyphenoloxidase and peroxidase inactivation in pineapple (Ananas comosus L.) puree during high-pressure and thermal treatments

Abstract Thermal and high pressure inactivation kinetics of polyphenoloxidase (PPO) and peroxidase (POD) in pineapple puree were developed within the domain of 0.1–600 MPa, 30-70°C and 0–20 min, in which, PPO was more resistant compared to POD. The inactivation orders ( n ) for PPO and POD during thermal treatment were 1.018 and 1.028, derived from n th order kinetic model; whereas n values for PPO and POD during high pressure domain (200–600 MPa/30–70 °C) were 0.991 and 0.995, respectively. Pressure and temperature acted in antagonistic manner on both the enzymes within 200–300 MPa; however, they became synergistic beyond 400 MPa. An empirical model considering the pressure dependency of activation energy and temperature dependency of activation volume was developed which adequately described the inactivation behavior of both enzymes. At 70 oC/20 min, high pressure like 600 MPa protected the bioactive components better in the sample than at 0.1 MPa. Industrial relevance Preparation of stable pineapple puree includes the requisite of inactivating the browning enzymes like polyphenoloxidase (PPO) and peroxidase (POD), which are responsible for less market value of the product. A detailed kinetic evolution of these enzymes is obligatory for the design and optimization of process to be applied, as both the oxidoreductases react in different way depending on the source and experimental domain. The stability of these enzymes has been compared between thermal and high-pressure processes. The developed empirical model in this study will help in identifying the optimum condition targeted towards the inactivation of browning enzymes during high-pressure processing of pineapple puree with an extended shelf-life.

Effect of pH on Enzyme Inactivation Kinetics in High-Pressure Processed Pineapple (Ananas comosus L.) Puree Using Response Surface Methodology

Effect of pH and high-pressure process treatments viz. pressure, temperature, and dwell time on inactivation of polyphenoloxidase (PPO), peroxidase (POD), bromelain (BRM), and pectinmethylesterase (PME) in pineapple puree was studied. Experiments were conducted according to rotatable central composite design (RCCD) within the range (−α to + α) of 100–600 MPa, 20–70 °C, and 0–30 min at three different pH levels (3.0, 3.5, and 4.0) followed by analysis through response surface methodology (RSM). Enzyme inactivation was significantly (p < 0.05) affected by all the process parameters, and temperature had the highest contribution among those. Enzyme inactivation kinetics was demonstrated with dynamic pressure-buildup period (pressure pulse effect) followed by static pressure-hold period (isobaric-isothermal first-order inactivation). Increased pulse effect (PE in log scale) values were obtained at lower pH and higher values of both pressure and temperature. Maximum PE values, obtained at 500 MPa/60 °C/pH 3, were 0.332, 0.319, 0.392, and 0.278 for PPO, POD, PME, and BRM, respectively. The inactivation rate (k in min−1) revealed that PPO was the most resistive (k ranged between 0.0020 and 0.0379 min−1) when compared with other three enzymes within the experimental domain. Increased k at lower pH with constant pressure and temperature depicted that pH had negative effect on the inactivation process. The optimized conditions targeting maximum inactivation of PPO, POD and PME with simultaneous retention of BRM in pineapple puree, were 600 MPa/60 °C/9 min, 600 MPa/60 °C/10 min and 600 MPa/60 °C/10 min for the samples of pH 3.0, 3.5, and 4.0, respectively.

Color degradation kinetics of pineapple puree during thermal processing

Improvement of color, as a quality attribute of processed pineapple puree, has been made possible by the increase in knowledge of kinetic of color change. The kinetics of color degradation of pineapple puree were investigated during heat treatment at 70–110 °C in order to cover the temperature range that used in preheat and sterilization of commercial aseptic pineapple puree. Color changes associated with heat-treated puree were monitored using Hunter colorimeter ( L, a, b, total color difference—Δ E) and Browning index ( A 420). The changes in L and b values fitted well to the first-order kinetic model while Δ E, a value, and Browning index followed the zero-order kinetic. The dependence of the rate constant on temperature was represented by an Arrhenius equation. The results suggested that Δ E and lightness, based on activation energy, were the most sensitive measures of color change at temperature range 70–90 and 95–110 °C, respectively.

Thermal inactivation of polyphenoloxidase in pineapple puree

Prevention of browning in pineapple puree by thermal inactivation of enzyme, Polyphenoloxisase (PPO), was examined between 40 and 90 °C and in relation to exposure time. The amount of inactivation was measured as a function of time and temperature under isothermal conditions. Reaction rate constant and activation energy ( E a) as well as Decimal reduction time ( D) and z-value of thermal inactivation, were determined. The rate of inactivation varied with temperatures and follows a logarithmic law. Kinetic studies showed that the thermal inactivation (40–90 °C) of the PPO followed first-order kinetics.