Determination of Thermal Process Schedule for Acidified Papaya

Nath, Nirankar; Ranganna, S.

doi:10.1111/j.1365-2621.1981.tb14564.x

Cited by 14 publications

(6 citation statements)

References 9 publications

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“…These authors found and purified various fractions of PE with different thermal stability. However, Nath and Ranganna (1981), reported higher D values for PE, (D,,c = 13.97 min), in a papaya syrup homogenate (pH 3.8). The presence of sugar may be responsible for increasing the resistance.…”

Section: Resultsmentioning

confidence: 84%

THERMAL INACTIVATION of PECTINESTERASE IN PAPAYA PULP (pH 3.8)

Magalhães¹,

Tosello²,

Massaguer³

1996

J Food Process Engineering

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In order to establish the thermal process required by acified papaya pulp (pH 3.8) var “formosa”, a study was carried out on the kinetics of thermal inactivation of the heat resistant enzymes present in the pulp. Since no peroxidase activity was detected, the study was focused on pectinesterase. The heat inactivation curves at 75, 77 and 80C showed a change in slope indicating the presence of two different portions of the enzyme, one heat labile and the other heat resistant. the decimal reduction times (D value) of pectinesterase were 0.8, 0.3 and 0.2 min for the heat labile portion and for the heat resistant portion 16.7, 7.2 and 3.7 min, respectively. The temperature‐dependency factor for the heat labile portion was 9.2C and 7.8C for the thermostable portion, while the activation energies were 258.3 and 304.4 Kj/mol. These values were within the range of 167.5–418.7 Kj/mol reported in the literature for the thermal inactivation of enzymes. Thermal destruction studies with Clostridium pasteurianum, conducted at the same temperatures used for the inactivation of the enzyme, showed that the heat resistant portion of pectinesterase presented greater thermal resistance and should be used as target for the establishment of the required process.

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Section: Resultsmentioning

confidence: 84%

THERMAL INACTIVATION of PECTINESTERASE IN PAPAYA PULP (pH 3.8)

Magalhães¹,

Tosello²,

Massaguer³

1996

J Food Process Engineering

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“…Nitrogen solubility index (NSI) was estimated using the method recommended by AOCS (1969). At each temperature, the minimum heating time to give no residual lipoxygenase activity in cotyledons was taken as thermal inactivation time (Nath & Ranganna, 1981). Soybean cotyledons were then blanched at 80, 85, 90, 95 or 99.3"C for these times, cooled in ice-cold water, dried either in the sun, or tray drier at 60+-2"C, and analysed for moisture, NSI, TIA and lipoxygenase activity.…”

Section: Methodsmentioning

confidence: 99%

A simple blanch‐dry process for lipoxygenase inactivation in soybean cotyledons

Seth

Nath

1988

Int J of Food Sci Tech

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Full-fat flour from unblanched soybeans develops a beany flavour during milling due to lipoxygenase activity; the flour also becomes bitter during storage. The minimum thermal treatment necessary to inactivate lipoxygenase in soybeans before milling was determined. Soybeans were dehulled and cotyledons blanched in water between 80 and 99.3"C. Water blanching for 3 min at 99.3"C was necessary when blanched cotyledons were subsequently sun dried, and the flour had a nitrogen solubility index (NSI) of 37.8% and residual trypsin inhibitor activity (TIA) of 64.2%. Only 1.5 rnin blanching was necessary to inactivate lipoxygenase in soy cotyledons if they were dried subsequently at 60°C; NSI of this flour was 32.7%, with 44.7% residual TIA.

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“…¤ The preliminary work of this paper was presented as a poster at the XXIII Reunio n Cient• Ðca del Grupo de Cromatograf• a y Te cnicas AÐnes, Pen8 • scola, Castello n, 19È21 October 1994. process and storage. The presence of an invertase in papaya was shown to be responsible for much of the conÑicting values reported for sucrose in papaya (Chan and Kwok 1976 ;Inglett and Charalambous 1979 ;Nath and Ranganna 1981). Carbohydrates in banana are mainly present in the form of starch, during ripening it is almost completely hydrolysed with the formation of sucrose, glucose and fructose (Marriot et al 1981).…”

Section: Introductionmentioning

confidence: 94%