ArticlePDF Available

Inhibition of polyphenol oxidase in banana, apple and mushroom by using different anti-browning agents under different conditions

Authors:
  • Vidyasagar University,Oriental Institute of Science and Technology

Abstract and Figures

Fruit are highly perishable and maintain an active metabolism during the postharvest phase. Polyphenol oxidase or PPO (EC 1.14.18.1) is considered the enzyme responsible for quality deterioration and browning in different fruits during postharvest period. Since enzymatic browning causes deterioration of sensory and nutritional quality and affects appearance and organoleptic properties, inactivation of PPO is desirable for preservation of foods. The objective of this study was to evaluate the antibrowning (inhibition of polyphenol oxidase activity) effect of Cysteine (Cys) , Ascorbic acid (AA), citric acid (CA), sodium metabisulphite(SMB) alone or in combination, at three different pH (3.5,4 and 4.5) in banana (Musa paradisiaca L. var. Kanthali), apple (Malus pumila Mill. var. Ambri kashmiri), and mushroom (Agaricus bisporus). All the samples were mixed with Cys (100, 200 and 300 mg/kg.), AA(250,500 and 1000 mg/kg.), CA (250, 500 and 1000 mg/kg.) and SMB (100,200 and 300 mg/kg.) to assess their effect on PPO. PPO activity was analyzed spectrophotometrically at 420 nm (30 0 C). The most effective PPO inhibitors were AA and SMB and in combination with CA and Cys in all the samples tested. No significant differences were observed for PPO activity among concentrations of Cys and CA when both anti-browning agents were used alone or in combination and mixed with the samples.
Content may be subject to copyright.
Int. J. Chem. Sci.: 8(5), 2010, S550-S558
________________________________________
*
Author for correspondence; E-mail: bidyut2006@gmail.com
INHIBITION OF POLYPHENOL OXIDASE IN BANANA,
APPLE AND MUSHROOM BY USING DIFFERENT ANTI-
BROWNING AGENTS UNDER DIFFERENT CONDITIONS
SAMANTA ARPITA, DAS SUBROTO, BHATTACHARYYA PINAKI and
BANDYOPADHYAY BIDYUT
*
Post Graduate Department of Biotechnology, Oriental Institute of Science and Technology, Dewandighi,
Mirjapur, BURDWAN – 02 (W.B.) INDIA
ABSTRACT
Fruit are highly perishable and maintain an active metabolism during the postharvest phase.
Polyphenol oxidase or PPO (EC 1.14.18.1) is considered the enzyme responsible for quality deterioration
and browning in different fruits during postharvest period. Since enzymatic browning causes deterioration
of sensory and nutritional quality and affects appearance and organoleptic properties, inactivation of PPO
is desirable for preservation of foods. The objective of this study was to evaluate the antibrowning
(inhibition of polyphenol oxidase activity) effect of Cysteine (Cys) , Ascorbic acid (AA), citric acid (CA),
sodium metabisulphite(SMB) alone or in combination, at three different pH (3.5,4 and 4.5) in banana
(Musa paradisiaca L. var. Kanthali), apple (Malus pumila Mill. var. Ambri kashmiri), and mushroom
(Agaricus bisporus). All the samples were mixed with Cys (100, 200 and 300 mg/kg.), AA(250,500 and
1000 mg/kg.), CA (250, 500 and 1000 mg/kg.) and SMB (100,200 and 300 mg/kg.) to assess their effect
on PPO. PPO activity was analyzed spectrophotometrically at 420 nm (30
0
C). The most effective PPO
inhibitors were AA and SMB and in combination with CA and Cys in all the samples tested. No
significant differences were observed for PPO activity among concentrations of Cys and CA when both
anti-browning agents were used alone or in combination and mixed with the samples.
Key words: Inhibition, Anti-browning agents, Banana, Apple and Mushroom Polyphenol oxidase,
Chemical treatment.
INTRODUCTION
Enzymatic browning is one of the most studied reactions in fruits and vegetables during
handling, processing and storage. The main enzyme involve in browning reaction is polyphenol
oxidase (PPO, Ec 1.14. 18.1). The activity of polyphenol oxidase has been extensively studied
and reported as the key factor in browning reaction
1
. PPO, also called tyrosinase, phenol oxidase,
cresolase are copper containing enzyme, synthesized in plants and stored in chloroplast
2
.
Polyphenol oxidase catalyzes the O-hydroxylation of monophenols to O- diphenols, which are
further catalyzed to produce O-quinones. Once formed, these quinones undergoes
Int. J. Chem. Sci.: 8(5), 2010
S551
polymerization reactions leading to the production of black, brown or red pigments
(Polyphenols) which is the cause of enzymatic browning in fruits and vegetables. So, it is
desirable to inactivate the PPO activity during preservation of foods as the enzymatic browning
change the physical appearance, sensory and nutritional quality of fruits and vegetables
3
. Now a
days, several methods have been used to inhibit the PPO activity, such as the use of Anti-
browning agents, removal of its one of the necessary component: O
2
, Cu
2+
etc or by thermal
processing to inactivate PPO activity is limited due to loss of sensory and nutritional quality of
fruits and vegetables
4
. Removal of oxygen from PPO can also check enzymatic browning but
browning may restart when oxygen is available
5
. So, the best way to prevent enzymatic
browning is the use of anti-browning agents. These agents act on the enzyme or react with the
substrate and/or products of enzymatic catalysis and thereby formation of browning pigment is
inhibited
6
. Several Anti-browning agents such as sulphites (Sulphur dioxide, sodium or
potassium metabisulfite, sodium or potassium bisulfite); acidulants such as citric, malic or
phosphoric acid; chelators (EDTA); reducing agents (ascorbic acid alone or in combination,
Cysteine); 4-hydroxyrecercinol etc have been extensively used for preventing browning of
foods
7,8
. Ascorbic acid reduces o-quinones to diphenols and prevents the formation of browning
pigments
9
. Sometimes ascorbic acid is oxidized completely and browning may occur due to
formation of melanins
10
. Acidifiers or acidulants can inhibit PPO activity by reducing pH and or
chelating copper in fruits and vegetables
11
. Cysteine reacts with O- quinones and forms a
colourless compound and thereby reduces PPO activity by delaying discolorations
12
. Another
anti-browning agent, 4- hydroxyresorcinol binds with PPO to form an inactive complex and
thereby reduces the browning reaction
13
. The objective of this study was to evaluate the anti-
browning (inhibition of PPO activity) effect of Cysteine, ascorbic acid, citric acid, sodium
metabisulfite alone or in combination, at three different pH (3.5, 4 and 4.5) in banana, apple and
mushroom.
EXPERIMENTAL
Materials and methods
Materials
Healthy, disease free Banana (Musa paradisiaca L. var. Kanthali), apple (Malus pumila
Mill. var. Ambri kashmiri), and mushroom (Agaricus bisporus) were purchased from the local
market.
Preparation of Crush
The materials were washed, held in ice water (1–2
0
C). Apple and banana were peeled,
de-seeded and cut into pieces. Mushrooms were sliced. Materials were blended in a domestic
blender to obtain a crush and kept in beakers (around 10–20 min) surrounded with ice water to
slow down discoloration. The crush was adjusted to desired pH (3.5, 4.0, or 4.5) with phosphoric
acid immediately after preparation. Crush (50 g) was weighed and mixed with sodium
metabisulphite (E. Merck), L-ascorbic acid (E. Merck), or L-cysteine hydrochloride hydrate (E.
Merck) and Citric acid (E. Merck) alone, or in combination as presented in Table 1. Each crush
A. Samanta et al.: Inhibition of Polyphenol Oxidase….
S552
was weighed (35 g) and placed into a sterile sample bag with remaining air evacuated and tabs
folded 8 times to seal the opening. Bags were then held in ice water until analysis for PPO
activity. The study was made in duplicate.
Table 1: Combination of different anti-browning agents used in this experiment
Treatments - Anti-browning agents
Cys (mg/kg) AA (mg/kg) CA(mg/kg)
SMB
(mg/kg)
0 100 200 300 250 500 1000 250 500 1000
0
0 4 5 6 16 17 18 28 29 30
100
1 7 8 9 19 20 21 31 32 33
200
2 10 11 12 22 23 24 34 35 36
300
3 13 14 15 25 26 27 37 35 36
PPO assay
PPO activity was assessed spectrophotometrically at 420 nm (30
0
C) in a UV-Vis
spectrophotometer (Elico, India)
14
. The PPO extract was obtained by mixing 10 g of apple,
banana and mushroom crush with 10 mL of sodium phosphate buffer (pH 6.6) at 5
o
C and
centrifuging at 4000 rpm for 40 min at 4
o
C. The extract was filtered with Whatman paper No. 1.
The supernatant was denominated as enzyme extract. The reaction mixture consisted of 2.2 mL
of buffer, 0.5 mL of catechol (0.175 mol/L), and 0.3 mL of enzyme extract. After mixing the
mixture the absorbance was recorded every 15 s for 3 min. The linear portion obtained in
plotting absorbance as a function of time was used to compute PPO activity. One unit of PPO
activity was defined as 0.001 A420/min/mL. All extracts were analysed in triplicate.
Statistical analysis
Data analysis was carried out using a Microsoft Excel 2003 and analysis of variance
(ANOVA) was performed with the SPSS 12.0 software. *P < 0.05 was selected as the decision
for significant differences.
RESULTS AND DISCUSSION
Banana, apple and mushroom crush containing SMB, Cys, AA and CA
PPO activity
PPO activity in banana, apple and mushroom crush at different pH (3.5,4.0 and 4.5) and
different concentrations of anti-browning agents were presented in Table 2,3 and 4 respectively.
From the tables, it can be concluded that the PPO activity decreased as the pH of the crush
materials decreased in case of all the three species studied. It was also observed that the PPO
activity was drastically decreased at pH 4 and pH 3.5 in all the three species, as compared to pH
4.5 (Fig. 1, 2 and 3). As the PPO activity is maximally observed between pH 5 and 7
13
, low pH
Int. J. Chem. Sci.: 8(5), 2010
S553
may inhibit, or minimize PPO activity due to acidification
11
. According to McEvily et al.
9
, PPO
was completely inhibited at a pH below 3. But fruit products generally do not possess this much
low pH and in this low pH the taste of such products become changed and it may be extremely
acidic for regular consumption. The anti-browning effect of SMB, AA, CA and Cys (used alone)
in banana, apple and mushroom crush were presented in Table 2, 3 and 4 respectively and a
comparative study was also carried out to determine the potentiality of different selected anti-
browning agents and were presented in Fig. 1 (for Banana), Fig. 2 (for Apple) and Fig. 3 (for
Mushroom). In general, maximum inhibition activity of PPO were observed at a concentration of
200 mg/kg SMB at pH-3.5 and 1000 mg/kg AA at pH-3.5 in case of banana crush; 300 mg/kg
SMB at pH-3.5 and 1000 mg/kg AA at pH-3.5 in case of apple crush; 200 mg/kg SMB at pH-4
and 1000 mg/kg AA at pH- 4 and 300 mg/kg cysteine at pH-4 in case of mushroom crush.
McEvily et al.
9
suggested that ascorbic acid inhibits PPO activity by reducing o-quinones to
diphenols and cysteine reacts with o-quinones to form a colourless compound and thereby
reduces PPO activity. AA contributes both weak acidic and strong reducing properties
15
that may
reduce the pH of crush. However, from the two-way ANOVA study, we can conclude that the
residual PPO activity at different pH and at different concentration of selected anti-browning
agents were significantly different from control (*P < 0.05).
Table 2: Residual PPO activity in banana crush containing different anti-browning agents
at various pH
Enzyme activity units
Anti-browning agents
PH
Species Concentration (mg/Kg) 3.5 4.0 4.5
Control
0.000
14.5±1.2 32.1±1.1 248.4±2.4
100 8.7±1.8 10.4±1.2 102.6±1.9
200 4.0±1.3 5.6±1.4 81.3±1.3
Sodium
metabisulfite
300 10.6±1.6 21.7±1.5 138.5±1.4
250 8.2±1.1 6.5±1.5 90.6±1.4
500 5.4±1.1 7.6±2.1 78.4±1.4
Ascorbic acid
1000 4.2±1.2 3.8±1.8 40.6±1.2
250 9.4±1.4 11.8±2.0 122.8±1.3
500 6.2±1.4 8.6±1.1 106.2±1.9 Citric acid
1000 5.2±1.6 5.8±1.0 92.8±1.4
100 8.6±1.9 10.8±1.8 118.2±1.2
200 6.0±1.1 5.4±1.2 84.6±1.8
Cystein
300 4.8±1.6 3.8±1.8 68.2±1.5
A. Samanta et al.: Inhibition of Polyphenol Oxidase….
S554
Table 3: Residual PPO activity in apple crush containing different anti-browning agents at
various pH
Enzyme activity Units
Anti-browning agents
PH
Species Concentration (mg/Kg) 3.5 4.0 4.5
Control
0.000 11.61±1.1 25.68±2.1 244.41±1.5
100 6.99±1.1 8.22±2.6 95.53±1.6
200 3.22±1.6 18.76±1.6 79.93±1.2
Sodium
metabisulfite
300 8.48±1.5 4.96±1.7 72.53±1.6
250 6.66±1.9 5.05±1.6 83.34±1.7
500 4.32±1.8 6.66±1.7 75.53±1.4
Ascorbic acid
1000 2.68±1.4 4.42±1.1 34.4±61.2
250 7.53±1.5 9.08±1.6 112.16±1.4
500 4.66±1.5 7.06±1.9 102.23±2.2
Citric acid
1000 4.16±1.6 3.83±1.7 87.77±2.6
100 8.44±1.3 10.22±1.5 108.33±1.5
200 7.03±1.5 8.71 ±1.6 77.56±1.9
Cysteine
300 6.22±1.3 7.43±1.8 62.19±1.4
Table 4: Residual PPO activity in mushroom crush containing different anti-browning
agents at various pH
Enzyme activity Units
Anti-browning agents
PH
Species Concentration (mg/Kg) 3.5 4.0 4.5
Control
0.000 39.66±1.1 41.77±2.3 322.22±1.4
100 98.33±1.3 17.87±1.9 174.29±1.9
200 20.5±1.3 7.78±1.1 105.56±1.5
Sodium
metabisulfite
300 13.60±1.9 36.56±1.7 98.02±1.4
250 10.03±1.5 10.98±1.2 117.77±1.3
500 36.66±1.8 12.84±1.8 132.49±1.8
Ascorbic acid
1000 22.99±1.9 6.35±1.4 68.61±1.6
250 11.96±1.6 19.26±1.2 184.22±1.9
500 13.62±1.4 11.78±1.3 137.8±1.1
Citric acid
1000 6.23±1.6 12.25±1.1 120.66±1.6
Cont…
Int. J. Chem. Sci.: 8(5), 2010
S555
Enzyme activity Units
Anti-browning agents
PH
Species Concentration (mg/Kg) 3.5 4.0 4.5
100 95.33±1.6 31.75±1.1 154.05±1.6
200 46.29±1.1 7.06±1.4 110.12±1.4
Cysteine
300 29.77±1.6 5.02±1.5 88.66±2.8
0
50
100
150
200
250
300
CP1P2P3Q1Q2Q3R1R2R3S1S2S3
Different antibrowning agent at different concentration
Enzy
m
e
Activity Units
pH 3.5
pH 4
pH 4.5
Fig.1: Residual PPO activity in banana treated with different anti-browning agents
C = Control; P1, P2 and P3 = SMB (100, 200 and 300 mg/kg ); Q1,Q2 and Q3 = AA (100,200 and 300
mg/kg ); R1, R2 and R3 = CA (100, 200 and 300 mg/kg ); S1,S2 and S3 = Cys (100,200 and 300 mg/kg )
0
50
100
150
200
250
300
C P1P2P3Q1Q2Q3R1R2R3S1S2S3
Different antibrownin
g
a
g
ent at different concentration
Enzy
m
e
activity units
pH 3.5
pH 4
pH 4.5
Fig. 2: Residual PPO activity in apple treated with different anti-browning agents. C = Control;
P1, P2 and P3 = SMB (100, 200 and 300 mg/kg ); Q1,Q2 and Q3 = AA(100, 200 and 300 mg/kg );
R1,R2 and R3 = CA(100 ,200 and 300 mg/kg ); S1,S2 and S3 = Cys (100 ,200 and 300 mg/kg )
A. Samanta et al.: Inhibition of Polyphenol Oxidase….
S556
0
50
100
150
200
250
300
350
C P1P2P3Q1Q2Q3R1R2R3S1S2S3
Different antibrowning agent at different concentration
Enzy
m
e
activity units
pH 3.5
pH 4
pH 4.5
Fig. 3: Residual PPO activity in mushroom treated with different anti-browning agents
C = Control; P1,P2 and P3 = SMB(100, 200 and 300 mg/kg ); Q1,Q2 and Q3 = AA(100, 200 and 300
mg/kg ); R1,R2 and R3 = CA(100, 200 and 300 mg/kg ); S1,S2 and S3 = Cys (100, 200 and 300 mg/kg ).
Banana, apple and mushroom with SMB/Cys, SMB/AA and SMB/CA
PPO activity
Table 5, 6 and 7 represents the residual PPO activity in banana, apple and mushroom
crush respectively (pH 3.5) containing different combinations of anti-browning agents. The
lowest PPO activity in banana crush was obtained after adding combinations of SMB/Cys
(200/300 mg/kg) and SMB/AA (100/500 mg/kg) (Table 5). The combinations of SMB/Cys
(100/200 mg/kg) and SMB/AA (100/250 mg/kg) were most suitable in reducing PPO activity in
apple (Table 6). From Table 7, it was observed that SMB/AA (100/500 mg/kg) and SMB/CA
(100/250 mg/kg) combinations in mushroom crush showed reduced PPO activity.
Table 5: Residual PPO activity in banana crush containing different anti-browning agents
at various pH
Enzyme activity units
Cys (mg/Kg) AA (mg/Kg) CA (mg/Kg)
SMB
100 200 300 250 500 1000 250 500 1000
100
4.6±1.2 4.8±1.3 8.1±1.1 3.8±1.7 3.2±1.3 5.4±1.7 5.2±1.1 6.2±1.2 8.9±1.6
200
5.5±1.2 6.0±2.1 4.1±1.4 5.1±1.6 8.4±2.2 8.8±1.7 7.6±1.9 5.6±1.7 9.2±1.1
300
8.9±1.7 11.6±1.1 7.6±1.4 8.8±1.8 9.6±1.7 9.4±1.8 11.8±1.2 10.6±1.4 11.8±1.5
Int. J. Chem. Sci.: 8(5), 2010
S557
Table: 6. Residual PPO activity in apple crush containing different anti-browning agents at
various pH
Enzyme activity units
Cys (mg/Kg) AA (mg/Kg) CA (mg/Kg)
SMB
100 200 300 250 500 1000 250 500 1000
100
3.6±1.9 3.4±1.2 6.5±1.6 3.2±1.3 3.9±1.6 4.4±1.1 4.1±1.7 4.9±1.4 6.9±1.4
200
4.5±2.1 5.1±1.2 3.3±1.5 4.1±2.2 6.7±1.7 7.2±2.1 6.0±1.5 4.9±1.8 7.2±1.8
300
7.1±1.1 9.1±1.3 5.9±2.1 7.0±2.5 7.4±1.4 7.8±1.8 9.4±1.1 8.4±2.1 9.4±1.1
Table 7: Residual PPO activity in mushroom crush containing different anti-browning
agents at various pH
Enzyme activity units
Cys (mg/Kg) AA (mg/Kg) CA (mg/Kg)
SMB
100 200 300 250 500 1000 250 500 1000
100
5.8±1.3 6.4±2.3 10.7±1.4 4.2±1.7 3.7±1.1 6.8±1.7 3.3±1.2 5.5±1.6 11.2±1.4
200
7.1±1.7 7.6±1.6 5.3±1.1 6.1±1.5 11.2±1.7 11.9±1.4 6.7±1.8 5.9±1.1 9.1±1.2
300
11.5±2.3 14.0±2.1 10.2±1.1 11.6±1.7 12.4±1.5 12.2±1.1 11.6±1.3 8.2±1.3 12.1±1.7
REFERENCES
1. J. R. L. Walker and P. H. Ferrar, Diphenol Oxidases, Enzyme catalysed Browning and
Plant Disease Resistance, Biotechnol. Genetic Engg. Rev., 15, 457-498 (1998).
2. V. Pilizota and D. Subaric, Control of Enzymatic Browning of Foods, Food Technol.
Biotechnol., 36, 219 (1998).
3. M. Hendrickx, L. Ludikhuyze, I. Vandenbroeck, and C. Weemaes, Effects of High
Pressure on Enzymes Related to Food Quality, Trends Food Sci. Technol., 9, 197-203
(1998).
4. N. Sun, S. Lee, and K. B. Song, Effect of High-Pressure Treatment on the Molecular
Properties of Mushroom Polyphenoloxidase, Lebensmittel- Wissenschaft Und-Technol.,
35, 315-318 (2002).
5. T. T. Langdon, Preventing of Browning in Fresh Prepared Potatoes without the use of
Sulfiting Agents, Food Technol., 41(64), 66-67 (1987).
6. O. Arslan and S. Dogan, Inhibition of Polyphenol Oxidase obtained from Various Sources
by 2,3-Diaminopropionic Acid, J. Sci. Food Agri., 85, 1499-1504 (2005).
A. Samanta et al.: Inhibition of Polyphenol Oxidase….
S558
7. N. Fayad, L., Marchal, C. Billaud and J. Nicolas, Comparison of Beta-Cyclodextrin Effect
on Polyphenol Oxidation Catalyzed by Purified Polyphenol Oxidase from Different
Sources, J. Agri. Food Chem., 45, 2442-2446 (1997).
8. G. M. Sapers, Browning of Foods : Control by Sulfites, Antioxidants and other Means.
Food Technol., 47, 75-84 (1993).
9. A. J. McEvily, R. Iyengar and W. S. Otwell, Inhibition of Enzymatic Browning in Foods
and Beverages, Critical Rev. Food Sci. Nut., 32, 253-273 (1992).
10. J. R. L. Walker, C. Y. Lee and J. R. Whitaker (Eds.), Enzymatic Browning in Fruits, in
Enzymatic Browning and Its Prevention, USA : American Chem. Soc. (1995) pp. 8-22.
11. T. Richardson and D. B. Hyslop, Enzymes, in, O. R. Fennema (Ed.), Food Chemistry, 2nd
Ed., USA, Marcel Dekker (1985) pp. 371-476.
12. E. D. Dudley and J. H. Hotchkiss, Cysteine as an Inhibitor of Polyphenol Oxidase, J. Food
Biochem., 13, 65-75 (1989).
13. H. S. Lambrecht, Sulfite Substitutes for the Prevention of Enzymatic Browning in Foods,
in C. Y. Lee and J. R. Whitaker (Eds.), Enzymatic Browning and its Prevention, American
Chemical Society USA (1995) pp. 313-323.
14. F. Pizzocaro, D. Torreggiani and G. Gilardi, Inhibition of Apple Polyphenoloxidase (PPO)
by Ascorbic Acid, Citric Acid, and Sodium Chloride, J. Food Process. Preservation, 17,
21-30 (1993).
15. S. T. Tannenbaum and V. R. Young, Vitamins and Minerals, in O. R. Fennema (Ed.),
Food Chemistry, 2nd Ed., Marcel Dekker, USA (1985) pp. 477-544.
... The tubers are used for preparing ayurvedic medicine as they are anti-inflammatory, anti-haemorrhoidal, astringent, haemostatic, digestive, appetizer, rejuvenating and tonic [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. The plant starch is easily extractable and with good viscosity, stability and suitability for many applications in food industry [2]. ...
... In microwave processing the energy is transferred directly to the sample producing a volumetric heating [7][8][9][10][11][12][13][14][15][16][17][18][19]. This rapid internal energy generation causes the pressure build up and results in rapid evaporation of water [6]. ...
... Enzymatic browning is the second largest cause of quality loss in fruits and vegetables. Since enzymatic browning causes deterioration of sensory and nutritional quality and affects appearance and organoleptic properties, inactivation of Polyphenol Oxidase (PPO) is desirable for preservation of foods [9]. Conventional hot water blanching of vegetables, widely used in industry, involves the immersion of the fresh product for a prescribed time into hot water kept at a constant temperature ranging from 70 to 100°C [10]. ...
Article
Full-text available
Abstract-Elephant Foot Yam was blanched at 80°C for 4 min in hot water and exposed to microwave treatment under different microwave power ranging from 300 W to 900 W and exposure time (1, 1.5 and 2 min) and then dried in convective dryer at 60°C to study their effect on microwave assisted convective drying characteristics. Drying time, average drying rate, effective moisture diffusivity, activation energy and rehydration ratio were various factors studied. Increased in microwave power and exposure time increased drying rate and decreased the drying time. The whole drying took place in falling rate period only. Midilli et al. model was found to describe the drying behaviour of elephant foot yam most precisely (highest R 2 = 0.9996; least RMSE = 0.0051). The effective moisture diffusivity values ranges from 4.2 × 10-10 to 1.1× 10-9 m 2 /s and activation energy from 3.14 to 4.48 W/g. From storage study and sensory evaluation with quality in terms of protein, total sugar, ash and oxalate content was found to be acceptable in all drying treatments. Based on oxalate content and drying characteristics, exposure of 900 W microwaves for 2 min followed by hot air drying at 60°C was found to be most acceptable.
... While several studies have reported anti-browning compounds with PPO-inhibiting activities (Landi et al. 2013, Samanta et al. 2010, the present finding lends credence to the prospects of natural products as alternative anti-browning agents. The reduction in the browning index exhibited by the treatments may be linked to their potential to reduce the activity of PPO. ...
... Additionally, ascorbic acid used as internal control in the present study reduced PPO activity as well as browning index. This is consistent with existing findings (Landi et al. 2013, Samanta et al. 2010. In contrast, all treatments showed no effect on the activity of POD. ...
Article
Full-text available
Background: The prevention of browning in fruits remains a great concern in the food industry. Objective: In the present study, we evaluated the anti-browning potentials of gallotannin and Annona muricata extract in red apple (Malus domestica). Materials and Methods: Apple slices were made and dipped in the different solutions; distilled water (control), 1 % gallotannin, 1 % Annona muricata extract or 1 % ascorbic acid. The treated apple slices were stored at 4 o C for 0, 7 and 14 days and used for the determination of the browning index, polyphenolic content, total protein, polyphenol oxidase and peroxidase activities. Results: The treatment with gallotannin, A. muricata and ascorbic acid reduced browning of apple for storage days 7 and 14. However, only gallotannin treatment preserved the polyphenolic content of the apple slices when compared to the control as well as the other treatment groups. Furthermore, all treatments reduced the activity of the polyphenol oxidase for days 0 and 7 storage, relative to the control. In contrast, the treatments had no effect on the peroxidase activity when compared to the control. Conclusion: Data support the anti-browning potential of gallotannin, A. muricata and ascorbic acid. Further, anti-browning potential of these naturally derived materials may be linked with their inhibitory actions against polyphenol oxidase.
... Enzymatic browning is the second largest cause of quality loss in fruits and vegetables. Since enzymatic browning causes deterioration of sensory and nutritional quality and affects appearance and organoleptic properties, inactivation of polyphenol oxidase (PPO) is desirable for preservation of foods (Samanta et al., 2010). Conventional hot water blanching of vegetables, widely used in industry, involves the immersion of the fresh product for a prescribed time in hot water kept at a constant temperature ranging from 70 to 100°C (Fellow, 1988). ...
Article
Drying characteristics and quality of the elephant foot yam slices processed with microwave pretreatment and convective drying were investigated. Elephant foot yam slices was blanched at 80°C for 4 min in hot water and exposed to microwave treatment under different microwave power ranging from 300 W to 900 W and exposure time (1, 1.5 and 2 min) and then dried in convective dryer at 60°C to study their effect on drying characteristics and quality. Drying time, average drying rate, and rehydration ratios were studied. Increase in microwave power and exposure time increased the drying rate and decreased the drying time. The whole drying took place in falling rate period only. Midilli et al. model was found to describe the drying behaviour of elephant foot yam most precisely (highest R 2 = 0.9996; least RMSE = 0.0051). From storage study and sensory evaluation with quality in terms of protein, total sugar and oxalate content dried samples were acceptable from all drying treatments. Based on oxalate content and drying characteristics, exposure to 900 W microwave power for 2 min followed by hot air drying at 60°C was the most acceptable to obtain the best quality dehydrated elephant foot yam slices.
... The hydroxylation of monophenols to diphenols that catalyzed by polyphenol oxidase, produces quinones. The quinones undergo polymerization and produce polyphenols (black, brown or red pigments) which lead to the browning reaction in fruits and vegetables (Arpita et al., 2010). Dopamine is defined as the crucial and the most reactive substrate for eISSN: 2550-2166 © 2021 The Authors. ...
Article
Bananas are fruits that quickly turn brown after being peeled or cooked. The browning reaction reduces the quality of the appearance and shelf life of banana jam. Therefore, this study was aimed to evaluate the effect of chemical blanching and anti-browning agents on reducing browning reactions and maintaining the quality of banana jam during storage. In this study, Musa paradisiaca cv. Nipah was used to produce banana jam. The banana jam was prepared using three different treatments. The first treatment was prepared without hot water blanching treatment and with the addition of ascorbic acid and sodium metabisulphite. The jam was prepared with banana pulp, sugar, citric acid, and pectin. This treatment act as a control. The banana jam for the second and third treatments was prepared using the same ingredients as treatment one. In the second treatment, the sliced banana was blanched in hot water (80°C) for 10 mins, whereas in treatment three, the banana slices were dipped into 1.5% of ascorbic acid solution at 80°C for 10 mins. During the cooking process, 0.1% of sodium metabisulphite was added into the jam, for treatments two and three. The jam was cooked until the temperature reached 105°C and the total soluble solids range from 68 - 70°Bx. The banana jam was filled in glass jars, sterilized in a hot water bath at 80°C for 10 mins, cooled to 27°C (room temperature) before being stored at room temperature. The analysis observed were pH, total soluble solids, titrable acidity, colour, browning index, and textural properties. The samples were stored at room temperature for 60 days. The observations were made every 15 days for two months. After 60 days of storage, all treatments showed positive changes and a significant difference (p<0.05) in physicochemical and texture analyses. Overall, hot water blanching and chemical treatments significantly reduced the browning reaction in the banana jam. Therefore, treatment three had the best ability to slow down the browning reaction and deterioration rate of banana jam during room temperature storage.
... Polyphenol oxidase activity was assessed by spectrophotometer at 420 nm as described by Samanta et al. [23]. The PPO extract was obtained by mixing 10 g of kiwifruit crush with 10 ml of sodium phosphate buffer (pH 6.6) at 5° C and centrifuging at 4000 rpm for 40 min at 5° C. The extract was then filtered with Whatman paper No. 1. ...
Article
Full-text available
The aim of the present study was to investigate the effects of osmo-dehydration using four anti-browning agents (ascorbic acid (AA), citric acid (CA), EDTA and 4-Hexylresorcinol (4-HR) on physico-chemical, color and browning phenomenon in commonly consumed fresh cut kiwis (var. Hayward) of Kashmir region. Osmo-dehydration was carried out using 60 % glucose + 1 % calcium chloride solution under ambient conditions and concentration of anti-browning agents-ascorbic acid, citric acid, EDTA and 4-HR were varied between 0.5 and 2.5 %, 0.5-1.5 %, 0.25-1.25 and 0.01-0.05 %, respectively, using central composite rotatable design. Browning index, polyphenol oxidase activity, and yellowness (b*) were significantly (p < 0.05) decreased, whereas brightness (L*) and greenness (-a*) were significantly (p < 0.05) increased with the increase in concentration of each anti-browning agent. Out of all the anti-browning agents tested, 4-HR recorded dominant linear effect on each parameter. Design expert predicted optimum concentrations of AA as 2 %, CA as 1.3 %, EDTA as 1 % and HR as 0.04 % for reducing browning and preserving color parameters during osmotic-dehydration of kiwifruit slices. Kiwifruit slices osmo-dehydrated with optimum concentration of anti-browning agents showed significantly (p < 0.05) higher water loss and lower water activity than fresh kiwifruits. Anti-oxidant activity and ascorbic acid of kiwi slices increased significantly (p < 0.05) when osmo-dehydrated with optimum concentration of anti-browning agents than kiwi slices osmo-dehydrated without anti-browning agents.
... Polyphenol oxidase activity was assessed by spectrophotometer at 420 nm as described by Samanta et al. [23]. The PPO extract was obtained by mixing 10 g of kiwifruit crush with 10 ml of sodium phosphate buffer (pH 6.6) at 5° C and centrifuging at 4000 rpm for 40 min at 5° C. The extract was then filtered with Whatman paper No. 1. ...
Article
Full-text available
The aim of the present study was to investigate the effects of osmo-dehydration using four anti-browning agents (ascorbic acid (AA), citric acid (CA), EDTA and 4-Hexylresorcinol (4-HR) on physico-chemical, color and browning phenomenon in commonly consumed fresh cut kiwis (var. Hayward) of Kashmir region. Osmo-dehydration was carried out using 60 % glucose + 1 % calcium chloride solution under ambient conditions and concentration of anti-browning agents- ascorbic acid, citric acid, EDTA and 4-HR were varied between 0.5 and 2.5 %, 0.5–1.5 %, 0.25–1.25 and 0.01–0.05 %, respectively, using central composite rotatable design. Browning index, polyphenol oxidase activity, and yellowness (b*) were significantly (p < 0.05) decreased, whereas brightness (L*) and greenness (-a*) were significantly (p < 0.05) increased with the increase in concentration of each anti-browning agent. Out of all the anti-browning agents tested, 4-HR recorded dominant linear effect on each parameter. Design expert predicted optimum concentrations of AA as 2 %, CA as 1.3 %, EDTA as 1 % and HR as 0.04 % for reducing browning and preserving color parameters during osmotic-dehydration of kiwifruit slices. Kiwifruit slices osmo-dehydrated with optimum concentration of anti-browning agents showed significantly (p < 0.05) higher water loss and lower water activity than fresh kiwifruits. Anti-oxidant activity and ascorbic acid of kiwi slices increased significantly (p < 0.05) when osmo-dehydrated with optimum concentration of anti-browning agents than kiwi slices osmo-dehydrated without anti-browning agents.
... Chilling injury symptoms were suppressed by arginine applied to pomegranate [9], tomato [10], and by cysteine on plum [11]. Studies on enzymic browning of fresh cut produce have reported that arginine inhibited browning of apple and lettuce [12] while cysteine reduced browning of lettuce [13], potato [14], pear [15], banana, mushroom and apple [16]. Of the other amino acids, phenylalanine was found to inhibit rotting of mango, avocado, citrus and strawberry [17] while glutamic acid inhbited rotting of pear [18], tomato [19], and methionine inhibited senescence of litchi [20]. ...
Article
Full-text available
The function of free amino acids in protein synthesis, as a source of energy and unique roles in catabolism have been well studied in plant development but their function in postharvest fruit and vegetables has received little attention. This study evaluated 11 amino acids—arginine, alanine, aspartic acid, glutamic acid, glycine, ornithine, phenylalanine, serine, tyrosine, tryptophan and valine—on the development of senescence of broccoli. Broccoli florets were dipped in 5 mM solution of amino acids, then stored at 10 °C in air containing 0.1 µL L−1 ethylene. Senescence was assessed by green life, ethylene production, respiration rate and ion leakage. Green life was increased by all the amino acids except valine. Similarly, ethylene production and ion leakage were decreased by all the amino acids except valine, while respiration rate was reduced by all amino acids. It is speculated that the early reduction in ethylene production could be the mechanism by which the amino acids delayed senescence. The beneficial effect of naturally occurring amino acids in inhibiting senescence has potential commercial relevance, as the amino acids have Generally Recognised As Safe (GRAS) status which should assist gain regulatory approval, and gain acceptance by consumers wary of synthetic chemicals on foods.
... The banana peel was removed from its fruit before cutting into pieces of 5 5 cm. with soaking in 0.1 % w / w citric acid solution for 5 min to limit the activity of endogenous enzymes (Arpita et al., 2010). The banana peel was dried at 55 ℃ for 20 h (final moisture content 6 to 7 % dry basis). ...
Article
Full-text available
This work was aimed at evaluating the properties of pectin from unripe cavendish banana peel using different acidic extractions. Hydrochloric (HCl), citric, and malic acid solutions at various pH values (1.5, 2.0, and 2.5) were used in this study. The properties of a raspberry jam added with the obtained pectins were also investigated. The extraction yield, galacturonic acid content, degrees of esterification (DE) and methylation (DM) of the samples were quantified and compared. The highest pectin yield was obtained using extraction with citric at pH 2.0. The citric extraction also gave the highest percentages of DE (50.27 %) and DM (59.57 %) at pH 1.5. Extraction with HCl gave higher galacturonic acid content to the extracted pectin. Additionally, the use of HCl at pH 1.5 also provided the highest gel hardness (30.26 g). For food application, most of the pectins significantly decreased raspberry jam hardness along with decreasing lightness and redness when compared with the control.
... increased in all anti-browning treated banana samples after 24 h of storage except KMS treatment(Figure 1). This could be due to sulfhydryl compounds in KMS that act on PPO enzyme during grinding which irreversibly binds with copper on active site and prevent the formation of browning compound until all the sulfite is used up(Valero et al., 1991).Arpita et al. (2010) also evaluated the effect of citric acid (CA), ascorbic acid (AA), cysteine (Cys) and sodium metabisulphite (SMB) on banana, ...
Article
Full-text available
Banana pulps (ripe and overripe) were taken to investigate the effectiveness of various anti‐browning agents (0.1 and 0.2% potassium metabisulphite (KMS), 1 and 2% citric acid (CA), 1% ascorbic acid (AA), 1% CA + 0.5% L‐cysteine, 1% CA + 0.5% CaCl2, 1% CA + 1% AA + 0.5% cysteine) to prevent enzymatic browning. Based on the polyphenol oxidase activity, color and sensory attributes, the most effective anti‐browning agent was selected. Results showed that KMS at 0.1% was most effective in inhibiting the browning reaction, which was further used for evaluating the effect of frozen storage (‐16°C) for 180 days along with control. But the control sample lasted for 30 days. In ripe pulp: TSS, total and reducing sugars increased whereas in overripe it decreased during storage but, the pH remained stable. The ascorbic acid, carotenoids, phenols and color value decreased for both samples slightly during freeze storage.
... PPOs are a group of copper-containing enzymes that are able to catalyze the oxidation of o-diphenol compounds to quinones (Steffens et al., 1994). In spite of their well-defined role in ultraviolet protection in animals, the physiological role of PPOs in plants has remained unclear and most studies have focused on the postharvest browning reactions observed in cut fruits and vegetables (Arpita et al., 2010;Walker, 1995). Roles of PPO have been demonstrated in biosynthetic processes (Mesquita and Queiroz, 2013;Mueller et al., 1997;Steiner et al., 1999;Strack et al., 2003), defense against herbivores Constabel, 2004a, 2004b), fungal pathogenicity, fungal defense reaction (Jacobson, 2000;Soler-Rivas et al., 2000), and resistance of plant to stress, wounding, pathogenesis, and stressrelated hormones such as methyl jasmonate (MeJA) and salicylic acid (Li and Steffens, 2002;Raj et al., 2006;Thaler et al., 1999;Thipyapong et al., 2004). ...
Article
Full-text available
Plants respond to pathogens with both active and passive defense mechanisms. These defense responses include the induction of defense or defense-related genes such as polyphenol oxidase (PPO) and pathogenesis-related (PR) proteins. The role of PPO in the interaction between bacterial blight [Xanthomonas arboricola pv. juglandis (Xaj)] and walnut (Juglans regia) was studied. JrPPO-1 and P14a genes were identified in two walnut cultivars, Chandler and Serr, using standard polymerase chain reaction (PCR) to understand their inducible ability in response to Xaj. ‘Serr’ and ‘Chandler’ were inoculated with Xaj strain 417. PPO activity in leaves was assayed at 0, 24, 72, 96, 120, and 144 hours after inoculation. Results showed a steady increase in activity commencing within 24 hours of inoculation. Increase in PPO activity was close to 2-fold greater in ‘Chandler’ than in ‘Serr’ at all time points examined. Real-time PCR analysis showed differences between cultivars in PPO gene expression. The JrPPO-1 gene was highly expressed in both cultivars 24 hours after inoculation but expression in ‘Serr’ was much greater than in ‘Chandler’. Significant expression of P14a gene was observed in both cultivars within 24 hours. Expression in ‘Serr’ was strong and maximized with a significant increase at 96 hours. Expression in ‘Chandler’ was far weaker than ‘Serr’ at 24 hours and did not increase further. Our results imply that the walnut–bacterial blight interaction induces the expression of JrPPO-1 and P14a as well as the activity of PPO.
Chapter
Enzymic browning in fruits is usually caused by catecholase (ortho-diphenol oxidase) enzymes whilst laccases (para-diphenol oxidase) are present in some fruits and many phytopathogenic fungi. The biochemical properties these enzymes is reviewed. Inhibition of catecholase as a means of prevention of enzymic browning is discussed and the properties of different classes of inhibitors reviewed. The possible roles of some of these inhibitors in the food industry is evaluated. Tests with selected substrates and inhibitors have been developed to differentiate catecholases and laccases.
Article
To elucidate the mechanism of pressure-induced denaturation of mushroom polyphenoloxidase (PPO), the enzyme was treated under 600 and 800 MPa, respectively, and its molecular properties such as secondary and tertiary structure were examined. High-pressure inactivation of the enzyme increased with pressure level and treatment time. Circular dichroism study showed that high-pressure treatment decreased the negative ellipticity values in the range 210–225 nm, resulting in change of the secondary structure of the enzyme. Fluorescence emission intensities also decreased with increase of high pressure and processing time, indicating changes in the tertiary structure of the enzyme. This study clearly shows that high-pressure treatment significantly alters the molecular properties of the enzyme.
Article
The effects of β-cyclodextrin (β-CD) on polyphenol oxidation catalyzed by apple polyphenol oxidase (PPO), endive PPO, or mushroom tyrosinase have been compared. β-CD forms a complex with phenolic substrates of PPO by inclusion. Assuming a 1:1 β-CD/phenol stoichiometry, and assuming that PPO is inactive on the complex β-CD/phenol, KD values were similar when determined kinetically by inhibition of apple PPO or endive PPO. However, the experimental velocities found during inhibition of mushroom tyrosinase by β-CD were higher than the values predicted by this model. In this latter case, it was assumed that mushroom tyrosinase is able to act on the complex β-CD/phenol. A new model based on this assumption allows experimental and calculated velocities to be fit in presence of β-CD. Keywords: Enzymatic browning; polyphenol oxidase; apple; endive; mushroom; inhibition; cyclodextrin
Article
The effect of L-cysteine on mushroom polyphenol oxidase (PPO) activity was investigated using three spectrophotometric assays. The formation of pigment (melanin), o-phenylquinone and cysteine-quinone adduct from catechol were each assayed under similar conditions. Cysteine had two effects; first, a lag phase was seen when melanin formation was measured, and secondly, the rate of browning was decreased after the lag phase. The lag phase was not observed when the formation of cysteine-quinone adduct rather than melanin formation was measured. This suggests that the lag phase observed in melanin formation is due to adduct formation and not quinone reduction. The velocity of adduct formation was similar to the velocity of o-phenylquinone and melanin formation without cysteine suggesting that reduction of o-phenylquinone to catechol was not significant. The structure of the adduct formed between cysteine and o-phenylquinone was synthesized and unequivocally determined by NMR spectroscopy to be S-(2,3-dihydroxyphenyl)cysteine.
Article
The inhibiting effect of ascorbic acid, citric acid and sodium chloride on Polyphenoloxidase (PPO) of Golden Delicious apple cubes was studied. Dipping in ascorbic acid (0.2-10 g/L range) and in NaCl (0.2-1 g/L range) solutions for 5 min increases the PPO activity. Citric acid solutions (0.2-10 g/L range) have little or no inhibition of PPO. A 90-100% PPO inhibition was obtained with a 5 min dip in mixtures of ascorbic acid and citric acid (10 + 2 g/L), and of ascorbic acid and sodium chloride (10 + 0.5 g/L).
Article
This paper reports for the first time the inhibition of the catecholase activities of mushroom, artichoke (Cynara scolymus L) and Ocimum basilicum L polyphenol oxidase by 2,3-diaminopropionic acid. Polyphenol oxidases from artichoke and O basilicum L were purified by ammonium sulfate precipitation, dialysis and a Sepharose 4B-L-tyrosine-p-aminobenzoic acid-affinity column. In inhibition studies, 2,3-diaminopropionic acid showed uncompetitive inhibition for mushroom PPO using catechol and pyrogallol as substrates, competitive inhibition for O basilicum L PPO using catechol as a substrate, and uncompetitive inhibition for artichoke PPO using catechol as a substrate. Furthermore, sodium azide, which is an inhibitor of PPO, was used as an inhibitor for comparison with the inhibition potency of 2,3-diaminopropionic acid. The highest 2,3-diaminopropionic acid inhibition observed with O basilicum L (Ki = 0.89 mM), followed by artichoke (Ki = 1.42 mM) and mushroom (Ki = 2.47 mM), respectively. Copyright © 2005 Society of Chemical Industry
Article
Quantitative relationships between enzymatic browning of foods and the responsible food constituents (e.g. phenol oxidase, phenolic substrates, inhibitors) are discussed. Attention is also given to the effects of extrinsic factors (e.g., climatic factors, fertilizers, phytohormones, pesticides,-irradiation, storage time and temperature) on the rates of browning.Quantitative Beziehungen zwischen enzymatischer Brunung von Lebensmitteln und den verantwortlichen Inhaltsstoffen (z. B. Phenoloxidase, phenolische Substrate, Inhibitoren) werden diskutiert. Darber hinaus wird ber die Effekte uerer Faktoren (z. B. Klima, Dngemittel, Phytohormone, Pesticide,-Bestrahlung, Lagerzeit und -temperatur) auf die Brunung berichtet.