Effects Of High Temperature Short Time Research Articles

Effects of pasteurization, microfiltration, and ultraviolet-c treatments on microorganisms and bioactive proteins in bovine skim milk

Effects of high-temperature short-time (HTST) pasteurization, microfiltration (MF) with 1.4/0.8 μm pore diameters, and ultraviolet-c (UV-C) irradiation with a coiled tube reactor on reducing microorganisms and somatic cells, and retaining bioactive proteins/enzymes along with protein oxidation in skim milk were studied. Bacteria were reduced by 2.3 log using HTST and UV-C, and 3.0 log using MF. Coliforms were not detected after all treatments. Spores were unaffected by HTST, reduced by 0.3 log using UV-C, and not detected after MF. Somatic cells remained unaffected by HTST and UV-C, and were undetectable after MF. Bioactive xanthine oxidase (XO), immunoglobulin G (IgG), lactoperoxidase (LPO), lactoferrin (LF), IgM, and IgA were retained at 87, 78, 69, 57, 48, and 41% using HTST, and 100% using UV-C and MF-1.4, while MF-0.8 retained fully the IgG and LPO, and 93, 92, 91, and 86% of IgA, XO, LF, and IgM. Native serum proteins were retained at 89% using HTST, 95% using UV-C, and 100% using MF. Carbonyls were increased by 26% using UV-C, and sulfhydryls were reduced by 14% using HTST, while both were unaffected using MF. Flux for MF-1.4 was higher and remained steady after an initial decrease of 12%, while flux for MF-0.8 decreased progressively by 45% until end of processing, resulting in complete and 89% passages of casein micelles using MF-1.4 and MF-0.8. MF-1.4 and UV-C could be proposed as nonthermal technologies alternatives or as hurdle-technologies to HTST for reducing microorganisms while retaining bioactive proteins/enzymes in skim milk, without inducing significant oxidative effects.

Comparative assessment of HTST, hydrodynamic cavitation and ultrasonication on physico-chemical properties, microstructure, microbial and enzyme inactivation of raw milk

The effects of high-temperature short time (HTST), ultrasonication (US) and hydrodynamic cavitation (HC) on physicochemical properties, alkaline phosphatase (ALP) activity, microorganism, degree of protein hydrolysis (DPH), color, microstructure and overall particle size of raw milk were studied. The separation index (SI) was also measured during storage of treated milk at 4 ± 2 °C for 12 days. US was carried out at different intensities (200, 300, and 400 W) and time (4, 6, and 8 min) and HC at 4, 6, 8, and 10 psi for 5, 10 and 15 min. It was observed that HC showed 21% energy efficiency (η) with higher cavitational yield than US which had η <10%. Microbial log reduction of 2.30 ± 0.17 TPC and 2.26 ± 0.17 (YM) was obtained by HTST treatment. And about 0.9 and 0.7 microbial log reduction were observed in HC and US treatment respectively. Initially in non-thermal treatment, ALP activity increases slightly by 1–2% at 4 psi (HC) and 200 W (US), but with further increase in time and intensity, ALP activity decreases. In addition to that, there was an increase in the DPH from 0.716 ± 0.09% to about 3.608 ± 0.52 and 3.77 ± 0.15% in US and HC treated samples respectively. Also, with an increase in time and intensity, number of fat globules increased with a decreased diameter and overall particle size. In non-thermal treatment, except for samples treated at 200 W (US) and 4 psi (HC), no separation was observed during the storage which could be due to reduced size of fat globules (from 6.3 μm to 3–2.2 μm).

Thermal and non-thermal processing effect on açai juice composition

This study evaluated the effects of High-Temperature Short Time (HTST), Ultra High Temperature (UHT), and the non-thermal processes High Power Ultrasound (US), UV-pulsed-light and Low Pressure Plasma (LPP) on the composition, stability, and bioactive compounds bioaccessibility of açai juice. 1H NMR based approach, coupled to chemometrics, was applied to evaluate the changes in the juice composition. All the non-thermal processes increased the sugars content (glucose and fructose), and the amino acid betaine, except the combined processing of ultrasound followed by low-pressure plasma (US.LPP). HTST and UHT increased the fatty acids and phenolic compounds content in the açai juice. The bioaccessibility of phenolic compounds decreased due to the processing. After thermal sterilization (UHT), the anthocyanin bioaccessibility was 2-fold higher. The combined non-thermal treatment reduced the biocompounds bioaccessibility to 40% of the non-processed juice. However, the combined US.LPP improved the bioaccessibility of vitamin C by 8%. UHT increased the anthocyanin’s bioaccessibility but sharply decreased vitamin C bioaccessibility. Higher impact of thermal processing on vitamin C, anthocyanins, total phenolics, PPO, POD, DPPH, ABTS, and FRAP was verified after 45 and 60 days of storage compared to the non-thermally processed samples.

Comparison of high temperature-short time and sonication on selected parameters of strawberry juice during room temperature storage.

The purpose of current research was to explore the effect of high temperature-short time (HTST) and different ultrasound times intervals on the strawberry juice for a period of 14days. Strawberry fruits were treated at 72°C for 15s by HTST and also sonicated at 20kHz and 100% amplitude for 5, 10, and 15min. The main objective is to evaluate the effect of treatments and storage time on color, total antioxidants, total phenolics, ascorbic acid and microbial content of strawberry juice. Results showed that the increase in the sonication treatment time (from 5 to 15min) showed a higher total phenolics, antioxidant capacity and ascorbic acid content. In addition, 15min sonicated-strawberry juices showed a higher lightness values as compared to HTST treated strawberry juice. Sonication treatment showed a potential as a method to preserve and improve the phytochemical quality of strawberry juice during room temperature storage.

The Effect of HTST and Holder Pasteurization on Bacterial Agglutination by Breast Milk

Background: Not only do infant formulas lack nutritional components supplied in breast milk, they lack a variety of maternal immune components normally transferred through breast milk, including microbial agglutinins. Bacterial aggregation by these agglutinins potentially reduces the likelihood of infection and is a critical step in the formation of the normal ecosystem of the infant’s gut, which is vital to proper immune system development. Objective: Given the need for better sources of breast milk for children who cannot receive their own mother’s milk, the effect of High Temperature, Short Time (HTST) pasteurization and Holder pasteurization methods on agglutinins in human breast milk was assessed. Methods: For this purpose, a small scale HTST pasteurization apparatus and protocol was created and validated. Bacterial aggregation was assessed indirectly by measuring initial changes in CFUs following post-pasteurization addition of exogenous bacteria, with less increase in CFUs being indicative of aggregation. Results: Raw milk and Holder pasteurized milk resulted in the fewest CFUs, with no difference observed between the two preparations. Interestingly, HTST pasteurized breast milk did not result in fewer CFUs than Holder pasteurized milk (p = 0.03), suggesting that the Holder method of pasteurization is at least as effective as HTST pasteurization at preserving bacterial agglutinins in human breast milk. Conclusion: Although more CFUs were observed in the assay using boiled human breast milk than any other milk preparation, the most CFUs were observed with infant formula, suggesting a propensity for that material to support uncontrolled planktonic bacterial growth.

Processing and matrix effects on the antioxidant capacity of fruit‐based beverages

Fruits contain a variety of polyphenolic compounds with antioxidant properties. These compounds are associated with lower risk of chronic disease. Fruits are consumed as raw and in processed forms (e.g. beverages). The perishable nature of fruits/fruit‐based products demands processing strategies to enhance shelf‐life and assure food safety, while maintaining nutritional quality. Therefore, we proposed to develop a system to test standard and novel processing strategies on the antioxidant capacity (AC) of fruit‐based beverages containing appreciable amounts of polyphenolic compounds. In this study, strawberry (Str) formulated dairy‐(D) and non‐ dairy (ND) beverages were used to investigate the effect of high temperature‐short time (HTS‐72°C‐20 sec) and high pressure (HPP‐600 MPa‐1 min) processing on AC as measured by Oxygen Radical Scavenging Capacity (ORAC). Two dairy‐based beverages contained 0 or 10 g, freeze‐dried CA Str (D‐Ctrl, D‐Str), and 1 beverage contained Str (10 g) and water only (ND‐Str). HPP and HTS reduced ORAC of D‐Str and D‐Ctrl compared to their respective unprocessed beverages (D‐Str: 6.9±1.1 &amp; 3.1±0.3 vs. 12.3±0.9 μMTE/mL and D‐Ctrl: 1.2±0.1 &amp; 1.8±0.2 vs. 2.4±0.2 μMTE/mL, respectively, P&lt;0.01). HPP did not affect ORAC of ND‐Str compared to unprocessed ND‐Str (11.1±1.0 vs. 10.6±1.1 μMTE/mL); however, HTS significantly reduced ORAC of ND‐Str (4.7±0.6 μMTE/mL) compared to unprocessed ND‐Str (P&lt;0.01). These findings indicate a significant effect of processing and matrix on AC of fruit‐based beverages and support further work to determine the impact of these findings in in vivo systems.

Modelling the water absorption process in chickpeas (Cicer arietinum L.)—The effect of blanching pre-treatment on water intake and texture kinetics

The effect of high temperature-short time (HTST) pre-blanching on water absorption and texture kinetics of chickpeas was investigated. Water intake and texture for both non-blanched and blanched chickpeas during soaking were evaluated for soaking within the temperature range 25–60°C. A first order asymptotic model was selected for primary modelling of sorption and texture data. Blanching at 100°C for 1.5min before soaking increased the rates of hydration and texture change for soak temperatures below 50°C. A change in the water absorption and texture kinetics occurred for blanched chickpeas at 37.5±1.5°C. Generalised non-linear models were proposed to describe the water absorption and texture kinetics. An uncertainty analysis of chickpea texture during soaking was performed to assess the influence of product texture variability. The results show that blanching followed by soaking at temperatures lower than 50°C shortens soaking times for chickpeas.