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The combined effects of heat and ultrasonic waves operating at absolute pressures between 1.5 and 7.2 kg/cm2 on peroxidase, polyphenol oxidase, and lipoxygenase inactivation have been studied over a broad range of temperatures, static pressures, and ultrasound amplitudes. A synergistic effect which can substantially reduce enzyme resistance and the heat treatment required for inactivation was observed in all cases. The peroxidase z value, estimated at 26 °C, was not changed by the combined treatment, but that of lipoxygenase increased from 4.2 °C (heat treatment) to 6.8 °C (combined treatment). The enzyme destruction efficiency of the combined process greatly increases with ultrasonic wave amplitude; decimal reduction times at constant temperature decreased logarithmically with increasing amplitudes. Static pressure does not seem to affect much the destructive effect of the combined process. This combined treatment could help to solve, in milk, juices, and other drinks, problems caused by thermostable enzymes.

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region 190-210 mjA was determined by Dr C. von Planta (Hoffmann-La Roche and Co., Basle) using a vacuum grating spectrometer as described by Planta (1962). Infrared-absorption spectra were recorded by a Perkin-Elmer Infracord (model 137) spectrometer. The highresolution spectra were obtained by Dr C. H. Steele of the Thornton Research Laboratories, Shell, Ellesmere Port, Cheshire, with a Grubb-Parsons double-beam grating spectrometer (model GS 2). Samples were examined as films between NaCl plates whenever possible. Materials of high melting point were studied as KBr disks.

Nitric oxide related ergogenic aids such as arginine (Arg) have shown to impact positively on sport performance through several physiological and metabolic mechanisms. However, research results have shown to be controversial. The great differences regarding required metabolic pathways and physiological demands between aerobic and anaerobic sport disciplines could be the reasons. The aim of this systematic review and meta-analysis was to evaluate the effects of Arg supplementation on aerobic (≤VO2max) and anaerobic (>VO2max) performance. Likewise, to show the effective dose and timing of this supplementation. A structured search was carried out in accordance with PRISMA® (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement and PICOS guidelines in PubMed/MEDLINE, Web of Science (WOS), and Scopus databases from inception to January 2020. Eighteen studies were included which compare Arg supplementation with placebo in an identical situation and testing its effects on aerobic and anaerobic performance tests. Trials analyzing supplementation with other supplements were removed and there was not athlete’s level, gender, ethnicity, or age filters. The performed meta-analysis included 15 studies and random effects model and pooled standardized mean differences (SMD) were used according to Hedges’ g. Results revealed that Arg supplementation could improve aerobic (SMD, 0.84; 95% CI, 0.12 to 1.56; magnitude of SMD (MSMD), large; I2, 89%; p = 0.02) and anaerobic (SMD, 0.24; 95% CI, 0.05 to 0.43; MSMD, small; I2, 0%; p = 0.01) performance tests. In conclusion, acute Arg supplementation protocols to improve aerobic and anaerobic performance should be adjusted to 0.15 g/kg of body weight ingested between 60–90 min before. Moreover, chronic Arg supplementation should include 1.5–2 g/day for 4–7 weeks in order to improve aerobic performance, and 10–12 g/day for 8 weeks to enhance anaerobic performance.