Identification and characterization of enzymatic browning inhibitors and antioxidant from Papaya Peel

Name: Faiq, Muhammad

LCSH: Kasetsart University -- Dissertations. Ph.D. (Food Science) 2019

Classification :.LCCS: TP372.55.E59

LCSH: Kasetsart University. -- Department of Food Science and Technology -- Dissertations

LCSH: Enzymatic browning

LCSH: Enzyme inhibitors

LCSH: Papaya Peel -- Utilization

LCSH: Antioxidants

LCSH: Phenols

Abstract: Enzymatic browning is the major problem in the fruits and vegetables, which contribute to quality loss. In this research, natural inhibitors from papaya peel were investigated for the enzymatic browning inhibition in fruits and vegetable, especially in potatoes. The highest L* value observed for the potato slices treated with papaya peel extract (PPE) after storage at 25 °C for six hrs. The highest chroma values (28.77) were also found for the potato slices treated with PPE at first hour followed by distilled water (24.85), while the lowest chroma values were that of potato slices treated with PPE (25.13). In apple slices, there was no significant difference of chroma values for slices treated with papaya peel extract and distilled water for six hour of storage (21.60 and 21.41) while significantly higher than that treated with the papaya seed extract (19.76). The L* values of potato slices treated with PPE were higher than that treated with distilled water through 2-6 h (p≤0.05). However, the L* values of the apple slices treated with PPE was lower than the treated distilled water through 1-6 h (p≤0.05). Results showed that PPE had % browning inhibition on potato slices higher than banana and apple slices at 1 and 3 h storage (p≤0.05), respectively. This might be due to the inhibition of the PPE on potato PPO by phenolic compounds. Total phenolic compound in PPE was 11.8 mg gallic acid equivalent /100 gm (dry weight basis). The effect of four different solvents on potato PPO inhibition was also studied. The highest PPO inhibition was found for ethyl acetate extract (75.12%) followed by the methanol extract (54.40%), while the ethanol extract showed the lowest PPO inhibition (29.24%). Water extract also showed the PPO inhibition (41.56%). Different ratio of water extract showed significant effect on PPO inhibition (p≤0.05). The highest polyphenol oxidase inhibition was recorded for the 1:3 (w/v) (84.5%) followed by 1: 9 (w/v) (57.0%). The highest total phenolic compounds were also found in the ratio of 1:3 (166.4 mg gallic acid equivalent/L) followed by 1:5 (125.31 mg gallic acid equivalent/L). The microwave-assisted extraction of PPE was also performed. The highest percent potato PPO inhibition was found for the microwave irradiated extract at 45 s followed by 30 s extract, while there was a decreasing PPO inhibition was observed upon the irradiation time of 60, 75 and 90 s. Two phenolic compounds in microwave assisted PPE were identified by HPLC. The results showed that caffeic acid and gallic acid were 17.12 and 10.01 µg/mL, respectively. The inhibition of these phenolic compounds on potato PPO was also tested. Caffeic acid showed potato PPO inhibition (80.02%) higher than gallic acid (27.13%). The kinetics study revealed that the inhibition of the potato PPO was mainly of mixed type inhibition by phenolic compounds detected in papaya peel extract.

Kasetsart University. Office of the University Library

Address: Bangkok

Email: tdckulib@ku.ac.th

Name: Chockchai Threerakulkait

Role: Thesis Advisor

Name: Pinthip Rumpagaporn

Role: Thesis Co-Advisor

Name: Kanithaporn Vangnai

Role: Thesis Co-Advisor

Created: 2019

Modified: 2025-06-29

Issued: 2025-06-29

วิทยานิพนธ์/Thesis

application/pdf

URL: https://www.lib.ku.ac.th/KUthesis/2562/muhammad-fai-all.pdf

CallNumber: TP372.55.E59 .F34

eng

DegreeName: Doctor of Philosophy

Level: Doctoral Degree

Descipline: Food Science

Grantor: Kasetsart University

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