Combined osmodehydration and high pressure processing on the enzyme stability and antioxidant capacity of a grapefruit jam

Influence of Cooking Technique on Bioaccessibility of Bioactive Compounds in Vegetable Lentil Soup

Vegetables and legume soups contain various essential and bioactive constituents such as vitamin C, carotenoids, and phenolics. Antioxidant activity characteristics related to those compounds are well known to contribute profusely to human health. The cooking technique affects the bioavailability of nutrients and bioactive compounds, making it crucial to explore optimal alternatives to maximize them. The objective of this study was to explore the influence of different cooking techniques (boiling, pressure cooking, sous-vide, and cook-vide) on the physicochemical properties and bioactive characteristics of a ready-to-eat vegetable lentil soup. For this, the bioaccessibility of those compounds was assessed through an in vitro simulated gastrointestinal methodology. The firmness of vegetables was established to define treatments' cooking times, allowing subsequent comparison of the nutritional and functional properties of the soups. The color of vegetables was also evaluated as a quality parameter, which contributed to providing a global vision of the process impact. The results revealed that in vitro digestion (IVD) caused a decrease in all bioactive compound determinations for all cooking treatments of up to 72% for total phenols, 92% for lycopene, 98% for carotenoids, and 100% for vitamin C. Additionally, the antioxidant activity of the soups after thermal treatment improved up to 46% measured by the DPPH method. This study emphasizes the importance of considering the digestion process in the selection of the most adequate cooking technique. After IVD, traditional cooking (boiling) reached the maximum total carotenoid and lycopene contents; cook-vide and pressure-cooking techniques provided the highest total phenol content, showing these three techniques to have the maximum antioxidant capacity.

Development of a reduced-calorie high pressure processed sapodilla (Manilkara zapota L.) jam based on rheological, textural, and sensory properties

High pressure technology (400 MPa at 27 ± 1.5 °C for 10 min) was applied for the processing of jam, and target was the reduction (∼47%) of sugar requirement by using a fiber-rich fruit, that is, sapodilla. Different formulations of jam containing various combinations of pectin (0.5 to 5.0%), sugar (45 to 65%), and acid (0.5 to 1) were investigated for textural, rheological, and sensory properties of the pressure-processed jam. The textural parameters mainly hardness (varied 16 to 594 g force) of the jam samples were significantly (P < 0.01) affected by the formulation ingredients viz. sugar and pectin content. Also, an interaction effect (P < 0.01) of sugar and pectin was observed on the jam hardness. The rheological parameters (gel strength, K') also varied (1036 to 2852 Pa) with the change in total soluble solids (TSS) and pectin content. However, the samples having lower TSS content (e.g. 45%) and appropriate pectin content (4.0, 4.5, or 5.0%) were similar (P > 0.05) to the samples having higher TSS content (65%) and corresponding pectin level (0.5, 1.0, or 1.5%) based on the rheological properties. On the other hand, the samples with middle levels of pectin at the corresponding TSS level (45 to 65%) were highest (score of >6 on seven-point hedonic scale) and equally preferred (P > 0.05) by the sensory panelist based on overall acceptability calculated from the scores obtained for sensory attributes viz. color, aroma, sweetness, sourness, texture, and spreadability. Therefore, the jam formulation containing sapodilla pulp as a base material, TSS 45%, pectin 4.5%, and citric acid 0.5% was determined to be the preferred formulation for the production of reduced-calorie, pressure-processed jam based on its gel strength, overall acceptability, and storage stability. PRACTICAL APPLICATION: High-fiber fruit was used for the development of a reduced-calorie high pressure processed jam in this study. The inherited or externally added fiber can favor the reduction in sugar requirement of a food product particularly those processed by high pressure, leading to reduction in calories. The findings of this study can be used for the development of novel HPP products with functional properties.

Kinetic modeling of high-pressure induced inactivation of polyphenol oxidase in sugarcane juice (Saccharum officinarum)

BACKGROUND

Polyphenol oxidase (PPO) is the main enzyme in sugarcane juice associated with rapid browning and degradation of organoleptic properties. High-pressure processing (HPP) (300-600 MPa) of sugarcane juice in combination with moderate temperatures (30-60 °C) for different processing times (10-25 min) has shown promising results in minimizing PPO activity while preserving the juice's freshness.

RESULTS

A maximum PPO inactivation of 98% was achieved at 600 MPa/60 °C/25 min, while the corresponding value for thermal treatment at 0.1 MPa/60 °C was only 66%. The nonlinearity in the inactivation data was well described by the Weibull distribution model with a high adjusted R² and reduced χ² values at all levels of pressure and temperature. The PPO inactivation data were fitted at shape parameter, β = 1 (log linear) and β ≠ 1. A refitted Weibull model was used to predict kinetic parameters such as the inactivation rate constants (k), activation energy (E_a ) and activation volume (V_a ), which govern PPO inactivation in HPP-treated sugarcane juice. A secondary kinetic model was formulated to predict the k values as a function of pressure (P) and temperature (T), incorporating E_a and V_a .

CONCLUSIONS

Combined high-pressure and temperature processing has been considered a reliable alternative to conventional heat treatment for inhibiting PPO activity in sugarcane juice. While the isothermal inactivation of PPO followed first-order kinetics, inclusion of high pressure resulted in a strong deviation from log linear kinetics. Identification of suitable kinetic models describing these inactivation processes is expected to aid product development and process control of high-pressure processed sugarcane juice. © 2018 Society of Chemical Industry.

Process kinetics on physico-chemical and peroxidase activity for different blanching methods of sweet corn

Blanching was performed to inactivate the enzyme using microwave, steam and hot water blanching methods and effect on the enzymatic activity, chemical properties and physical properties of the sweet corn were studied. The effectiveness of each blanching process was evaluated by measuring the loss of peroxidase activity, which was lost after 60, 90 and 120 s with k-values 0.016, 0.024 and 0.028 s^-1 following first order kinetics for microwave, steam and hot water blanching respectively. The total sugar, ascorbic acid, moisture content, kernel mass and geometric diameter changed from 8.40 to 6.30, 7.20 and 7.50 g/100 g; 7.15 to 5.70, 6.10 and 6.60 mg/100 g; 76 to 79.20, 78.20 and 75.30%; 0.47 to 0.53, 0.50 and 0.42 g; 8.00 to 8.50, 8.30 and 7.20 mm at optimum level of blanching during microwave, steam and hot water blanching respectively, indicating higher retention of total sugar and ascorbic acid in microwave blanching. The change in colour, especially increase in brownness was observed during blanching processes. The average R² for zero-order model was 0.945, suggesting use of model for prediction of physico-chemical parameters during blanching process of sweet corn.

Use of high pressure technology for the development of novel jam and its quality evaluation during storage

Jam like product was prepared using high pressure (HP) processing technology and was compared with thermally processed one for quality attributes. Strawberry pulp was mixed with pectin (1%) and sugar and packed in low density polyethylene pouches (50 g pack size) and processed at 200, 400 and 600 MPa for 30 min at 50 °C. Ascorbic acid, anthocyanins, phenolics, flavonoids and antioxidant activities were found to be significantly retained to a better extent in HP processed jams as compared to thermally processed one. The CIE L*, a* and b* values decreased significantly with increase in pressure, the decrease being of much lesser extent compared to thermally processed one. Increase in pressure was found to increase the sensory attributes for colour, appearance, flavour, texture and overall acceptability significantly; however, the scores were comparatively lesser than that of thermally processed jam. The sample processed at 600 MPa showed a shelf-life of 3 months on the basis of physico-chemical, sensory and microbial attributes when stored at ambient storage conditions (28 ± 5 °C).

High pressure effects on the structural functionality of condensed globular-protein matrices

High pressure technology is the outcome of consumer demand for better quality control of processed foods. There is great potential to apply HPP to condensed systems of globular proteins for the generation of industry-relevant biomaterials with advanced techno- and biofunctionality. To this end, research demonstrates that application of high hydrostatic pressure generates a coherent structure and preserves the native conformation in condensed globular proteins, which is an entirely unexpected but interesting outcome on both scientific and technological grounds. In microbiological challenge tests, high pressure at conventional commercial conditions, demonstrated to effectively reduce the concentration of typical Gram negative or Gram positive foodborne pathogens, and proteolytic enzymes in high-solid protein samples. This may have industrial significance in relation to the formulation and stabilisation of "functional food" products as well as in protein ingredients and concentrates by replacing spray dried powders with condensed HPP-treated pastes that maintain structure and bioactivity. Fundamental concepts and structural functionality of condensed matrices of globular proteins are the primary interest in this mini-review, which may lead to opportunities for industrial exploitation, but earlier work on low-solid systems is also summarised presently to put recent developments in context of this rapidly growing field.

Combined effect of high hydrostatic pressure and mild heat treatments on pectin methylesterase (PME) inactivation in comminuted orange

BACKGROUND

Comminuted orange, a product obtained by grinding the juice and peel and used to formulate beverages, has a high pectin methylesterase (PME) activity; thus the inactivation of this enzyme is necessary to avoid quality losses related to cloud loss. The use of high hydrostatic pressure (HHP) and mild temperature allows inactivation of enzymes with minimal quality changes. This work aimed to evaluate the effect of pressure, mild temperature and time of treatment, including come-up and holding time, on the inactivation of PME in comminuted orange, and to apply kinetic and response surface models (RSM) to predict residual PME activity (A/A0 ).

RESULTS

During come-up time in treatments at 68 °C, the higher the pressure, the lower was the A/A0 obtained. At 550 MPa/68 °C/10 min the lowest residual activity value was obtained (15.6%). A/A0 was well adjusted to the RSM, and a first-order kinetic model was applied to describe the inactivation of PME. In general, the higher the pressure, the lower was the A/A0 reached, as the increasing values of k from 3.5 × 10(-2) to 55.5 × 10(-2) min(-1) indicated. Activation volume (Va ) values ranging from -9.2 to -17.7 cm(3) mol(-1) , and activation energies (Ea ) between 50.0 and 68.2 kJ mol(-1) were calculated.

CONCLUSION

550 MPa/68 °C/10 min, 350 MPa/68 °C/10 min and 450 MPa/56 °C/10 min treatments were satisfactory (∼84% inactivation) to inactivate PME. A first-order kinetic model was applied to describe PME inactivation, and the resulting A/A0 adjusted to the RSM. In addition, linearized Arrhenius and Eyring equations were well fitted in order to obtain Ea and Va , respectively.

High Pressure Treatment in Foods

High hydrostatic pressure (HHP), a non-thermal technology, which typically uses water as a pressure transfer medium, is characterized by a minimal impact on food characteristics (sensory, nutritional, and functional). Today, this technology, present in many food companies, can effectively inactivate bacterial cells and many enzymes. All this makes HHP very attractive, with very good acceptance by consumers, who value the organoleptic characteristics of products processed by this non-thermal food preservation technology because they associate these products with fresh-like. On the other hand, this technology reduces the need for non-natural synthetic additives of low consumer acceptance.