Acid components of fruit and vegetable I. Production of acids by thermal processing

Crean, David E.

doi:10.1111/j.1365-2621.1966.tb01029.x

Cited by 6 publications

(1 citation statement)

References 9 publications

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“…Η επεξεργασία του χυμού τομάτας έχει ως αποτέλεσμα την αύξηση της ολικής οξύτητας στο τελικό προϊόν. Στη διεθνή βιβλιογραφία έχει αναφερθεί αύξηση της περιεκτικότητας σε οξικό οξύ σε ποσοστό 32% και αποδόθηκε στην οξείδωση αλδεϋδών και αλκοολών χυμού τομάτας κατά την επεξεργασία (Crean, 1966).…”

Section: σύσταση της τομάταςunclassified

Μελέτη Της Επίδρασης Των Παραμέτρων Της Διεργασίας Υπερυψηλής Υδροστατικής Πίεσης Στα Ένζυμα Της Τομάτας Και Εφαρμογή Για Την Παραγωγή Προϊόντων Με Επιθυμητά Χαρακτηριστικά

Boulekou¹,

Μπουλέκου²

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The objective of this work was to study the application of High Hydrostatic Pressure (HHP) on quality attributes of tomato products. Textural properties of tomato fruit play an important role to the overall quality in both fresh market and processed tomatoes and can be attributed to the activity of the pectinolytic enzymes such as pectin methylestarase (PME) and polygalactouronase (PG). The effect of high hydrostatic pressure processing on the endogenous tomato enzymes, PME and PG, was kinetically studied. The enzyme inactivation kinetic study was performed using three different tomato varieties: Cherry tomatoes (Lycopersicon esculentum variety Cherrelino) and two industrial hybrids namely Oval Red and Red Sea.The inactivation of PME and PG in freshly squeezed Cherry tomato juice was studied in the pressure range of 0,1-800 MPa combined with temperatures ranging from 40 to 80°C. The decrease of enzyme activity during thermal and pressure inactivation for both PME and PG followed first-order kinetics. PME in Cherry xii tomato juice was found to be pressure-stable and an antagonistic effect of pressure and temperature was observed. On the other hand, PG was more sensitive to pressure than PME. The PG inactivation rate constant increased with increasing pressure at all temperatures tested indicating a synergistic effect of pressure and temperature. The effect of HP processing on cherry tomato juice quality attributes were studied at selected processing conditions. The HP processing conditions did not significantly affect the color and lycopene content of tomato juice. Furthermore HP processing allowed total PG inactivation with concurrent remaining PME activity leading to high quality products in terms of viscosity and textural properties.The inactivation of PME and PG in tomato juice from Oval Red and Red Sea hybrids, was kinetically studied in the pressure range of 0,1-400 MPa combined with temperatures ranging from 40 to 80°C. PG inactivation in both thermal and high pressure processing deviated from 1 st order kinetics and was described by an n th order model for both tomato hybrids. PG was found to be extremely thermotolerant, 60% Oval Red PG inactivation was observed only when tomato juice was thermally treated at 80°C for one hour. Red Sea PG was found to be more temperature sensitive than Oval Red PG.On the other hand PG activity was extremely sensitive when thermal treatment was combined with pressure. HP treatment at 400 MPa combined with temperature of 70°C led to total PG inactivation. In the case of Oval Red juice a synergistic effect of pressure and temperature was observed on PG inactivation. However, according to the results an antagonistic effect of pressure and temperature was observed in pressures lower than 200 MPa combined with high temperatures (70°C) in Red Sea tomato juice. PME inactivation was kinetically studied in thermally and HP treated OvalRed and Red Sea tomato juice. Tomato juice was thermally treated in the temperature range of 50-80°C. High pressure processing from 100 to 800 MPa wa...

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Section: σύσταση της τομάταςunclassified

Μελέτη Της Επίδρασης Των Παραμέτρων Της Διεργασίας Υπερυψηλής Υδροστατικής Πίεσης Στα Ένζυμα Της Τομάτας Και Εφαρμογή Για Την Παραγωγή Προϊόντων Με Επιθυμητά Χαρακτηριστικά

Boulekou¹,

Μπουλέκου²

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Carboxylic Acids

Woodman

1985

Coffee

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Organic Acid Profiles of Thermally Processed, Stored Spinach Puree

Lin

Clydesdale

Francis

1971

Journal of Food Science

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— Deaerated spinach puree was packed into TDT tubes, flushed with nitrogen and sealed. The tubes were divided into batches and processed with an Fo = 4.9 at temperatures ranging from 240–300°F with 10°F increments. Analyses were carried out immediately after processing and after storage for 3 months at 75°F in the dark. Organic acids were analyzed by means of an Automatic Organic Acid Analyzer (AOAA) with confirmation by paper chromatography. Oxalic acid showed poor resolution on the AOAA; therefore, a chemical method was used for analysis. pH measurements were taken and color measured on a Hunterlab Model D25 Color Difference Meter. Catalase determinations were done on the stored samples. After processing, the greatest changes were noted at 240°F, with only minor changes above 280°F. Acetic and pyrrolidone‐carboxylic acid (PCA) showed the most change after processing. After storage, the concentration of acids, color and pH was similar for all packs and all proved catalase negative. During storage succinic, PCA and acetic acids showed the greatest increase with the latter two increasing the most at higher temperatures. Also, during storage α‐ketoglutaric acid disappeared and pyruvic, glutaric, oxaloacetic and malonic acids were formed at all processing temperatures.

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Acid components of fruit and vegetable I. Production of acids by thermal processing

Cited by 6 publications

References 9 publications

Carboxylic Acids

Organic Acid Profiles of Thermally Processed, Stored Spinach Puree

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