Journal of Food Science and Technology

, Volume 52, Issue 1, pp 335–342

Influence of 1-MCP treatments on eating quality and consumer preferences of ‘Qinmei’ kiwifruit during shelf life

Authors

  • Lei Deng
    • College of Food Science and EngineeringShandong Agricultural University
  • Cai-Zhong Jiang
    • Crops Pathology and Genetics ResearchUSDA
  • Wenliang Mu
    • Shandong Provincial Research Centre for Engineering and Technology of Food Safety of Fruits and Vegetables
    • College of Food Science and EngineeringShandong Agricultural University
Original Article

DOI: 10.1007/s13197-013-0986-y

Cite this article as:
Deng, L., Jiang, C., Mu, W. et al. J Food Sci Technol (2015) 52: 335. doi:10.1007/s13197-013-0986-y

Abstract

In recent years, some Chinese distributors said that 1-MCP treated kiwifruit were difficult to ripen and that the eating quality was reduced. This paper addresses whether these problems exists or not, determines the quality parameters affecting consumer preferences and reevaluates the necessity of 1-MCP application for storage of kiwifruit. ‘Qinmei’ kiwifruit (Actinidia deliciosa C.F. Liang et A.R. Ferguson) harvested at three ripening stages were treated with 0.5, 0.75, 1.0 or 1.5 μLL−1 1-MCP before cold storage. The results showed that for the fruit harvested at two higher ripening stages, 1-MCP treatment reduced decay incidence after 12 days shelf life following 90 days cold storage, and the percentage of decayed fruit for 1-MCP treatment was much lower than control after 150 days storage as well as on subsequent shelf life no matter what the ripening stage was. After decayed fruit was removed from all the treatments, fruit treated with 1-MCP displayed a lower consumer acceptance, especially at higher concentrations, compared with control during shelf life. This indicated 1-MCP treated fruit presented lower eating quality compared to control fruit during the shelf life. Excessive sourness, but not firmness or soluble solids was the main factor decreasing the taste of kiwifruit treated with 1-MCP. Fruit softening was delayed by all dosages of 1-MCP. However, the higher firmness showed no significant negative effect on eating quality. 1-MCP had no influence on soluble solids content after the cold storage or during shelf life. Our study demonstrated that utilization of lower concentration of 1-MCP up to 1 μLL−1 for ‘Qinmei’ kiwifruit with intended storage of 150 days was necessary, but not for 90 days storage of fruit harvested at low ripening stage (harvested at 6.4 % SSC).

Keywords

KiwifruitEating quality1-methylcyclopropeneTitratable acidityShelf lifeStorage

Introduction

Although diverse kiwifruits are planted in China, the A. deliciosa cultivar ‘Qinmei’ kiwifruit occupies more than 40 % of the entire planting acreages, which mainly distributes in Shaanxi province (Huang and Ferguson 2001). ‘Qinmei’ fruit is generally harvested in October, stored at 0 °C and then sold before Spring Festival on January or February, the most important holiday in China.

Due to extreme sensitivity to ethylene, storage life and fruit quality of kiwifruits are limited in terms of commercial demand (Crisosto et al. 2000). Thus, ethylene action inhibiter, 1-MCP has been registered for application during its cold storage in many countries. Application of 0.5 μLL−1 1-MCP on ‘Hayward’ kiwifruit after harvest significantly inhibited fruit softening at 20 °C after short and medium term cold storage, without affecting soluble solids contents (Koukounaras and Sfakiotakis 2007). Also, ‘Hayward’ kiwifruit treated with 1 μLL−1 1-MCP immediately after harvest showed a delay ripening rate and higher titratable acidity compared with control fruit within 4 weeks at 1.1 °C storage, and 1-MCP lost effect after 4 weeks storage (Carlos et al. 2001). Furthermore, low ethylene production was observed in kiwifruit treated with 0.5, 1 or 1.5 μLL−1 1-MCP after 30 days storage at 0.5 °C (Boquete et al. 2004).

It appears that inferior flavor, severe sourness and difficulty to ripen in ‘Qinmei’ kiwifruit treated with 1-MCP were observed in recent years by distributors, handlers or consumers in China, which lowered the local handler’s confidence in application of 1-MCP. We hypothesize that situation mentioned above may be caused by improper maturity at harvest which may influence the storage life and eating quality (Kader 1999), and/or by excessive 1-MCP application on kiwifruit.

The objective of this research was to examine effects of 1-MCP treatments on the quality of ‘Qinmei’ kiwifruit when different ripening stages of fruits were treated with different concentration of 1-MCP and stored at 0 °C cold room for 90 or 150 days.

Materials and methods

Plant material

Kiwifruits were harvested on October 7, 17, 24, 2010, respectively, in a commercial orchard in Shaanxi province, China. Fruits were harvested at three ripening stages, stage 1 (soluble solids content (SSC) 6.4 %), stage 2 (SSC 7.0 %) and stage 3 (SSC 7.5 %). For each ripening stage, 1500 good quality fruits were selected and then divided randomly into 5 groups of 300 kiwifruits. All fruits were stored at 0 °C for further analysis.

1-MCP treatment

Five groups of kiwifruits from each ripening stage were placed in identical sealed steel containers and fumigated with 0 (control), 0.5, 0.75, 1.0, 1.5 μLL−1 1-MCP (Xianfeng®, Jinan, China) at 0 °C (Temperature used in commerce in China) for 24 h. Following treatment, kiwifruits were stored at 0 ± 0.5 °C (90–95 % RH). Subjective eating quality and objective parameters were measured every 3 days during shelf-life after 90-day and 150-day cold storage.

Subjective eating quality evaluation and fruit decay

After decay fruit were removed, subjective eating quality evaluation was conducted on day 0 (the day before kiwifruits transferred to 20 °C), 3, 6, 9, 12 of shelf life by a trained panel including 20 male and 20 female, ages 18–50.

After washing, kiwifruits were sliced into 2 × 4 cm pieces immediately before evaluation and placed in easy lock containers. Each panelist received three pieces of fruit per treatment and then scored the values of “liking”. Overall liking degree was evaluated on a 9 to 1 scale, where 9 = excellent, no defects, 7 = good, minor defects, 5 = fair, moderate defects, 3 = poor, major defects, 1 = unusable. A score of 6 was considered the limit of salability. The score assessment of each evaluation was based on integrated factors including flesh color, smell, mouthfeel, taste, sweat/sourness ratio, and the main factor affecting overall liking was wrote down. Decay fruit did not involved in sensory evaluation.

Decay percentage was investigated on day 90 or 150 during cold storage and on day 12 during subsequent shelf life. Any fruit with symptoms of soft rot flesh or visible mold on surface was recognized as decayed one.

Objective evaluation of firmness, soluble solids content and titratable acidy

Every three days during shelf-life, kiwifruits were taken from each treatment and used for firmness, SSC and titratable acid measurements before eating quality evaluation. Firmness was measured at two sides of fruit after skin removed, using a firmness penetrometer (Wanger Instruments, US) with a 7.9 mm tip, and recorded in newton. Juice was collected onto a digital refractometer (ATAGO PAL-1, Tokyo, Japan) for SSC measurement of Brix. Titratable acid was determined by titration with 0.1 N NaOH to pH 8.2 and expressed as citric acid.

Statistical analysis

Data of the three replicates were statistically analyzed with mean separation by Duncan’s ANOVA at 0.05 level using SPSS program (version 17.0, SPSS Inc., Chicago).

Results and discussion

Eating quality

On day 0 during shelf life after 90 days storage, fruit showed no difference between control fruit and 1-MCP treatments in terms of overall liking score (Table 1). As the shelf life advanced, score values increased for all treatments. The highest scores of 8.74 (S1), 8.86 (S2), 8.36 (S3) were obtained from control fruit on day 9 shelf life. During shelf life, the taste scores for 1-MCP treatments were lower than that of control fruit. No significant difference was observed among 1-MCP treatments until day 6 for each ripening stage. Score in kiwifruit treated with 0.5 and 0.75 μLL−1 1-MCP was significantly higher than that of fruit treated with 1.0 and 1.5 μLL−1 1-MCP on day 6, 9, 12, suggesting that higher concentration of 1-MCP treatments adversely influenced on the consumer acceptance.
Table 1

Overall liking score of kiwifruit during shelf life at 20 °C after 90 days storage

Ripening stage

Shelf life(days)

1-MCP Concentration (μLL−1)

Control

0.5

0.75

1.0

1.5

Stage 1

0

4.9 ± 0.61 Ad

4.7 ± 0.34 Ac

5.1 ± 0.45 Abc

4.7 ± 0.36 Ab

4.5 ± 0.57 Ab

3

5.2 ± 0.33 Ad

4.8 ± 0.55 Ac

4.9 ± 0.32 Ac

4.8 ± 0.14 Ab

4.7 ± 0.34 Ab

6

6.1 ± 0.40 Ac

5.4 ± 0.32 Bb

5.5 ± 0.44 Bb

5.3 ± 0.30 Bb

5.1 ± 0.35 Bb

9

8.7 ± 0.42 Aa

7.3 ± 0.58 Ba

7.1 ± 0.76 Ba

6.5 ± 0.76 Ca

6.6 ± 0.62 Ca

12

7.7 ± 0.52 Ab

7.3 ± 0.24 Aa

7.3 ± 0.27 Aa

6.9 ± 0.39 Ba

6.8 ± 0.80 Ba

Stage 2

0

5.2 ± 0.28 Ac

5.1 ± 0.23 Ab

5.3 ± 0.38 Ab

5.0 ± 0.43 ABb

4.4 ± 0.38 Bb

3

5.9 ± 0.58 Ac

5.1 ± 0.18 Bb

5.2 ± 0.28 Bb

4.6 ± 0.25 Cb

4.6 ± 0.40 Cb

6

7.6 ± 0.61 Ab

5.5 ± 0.47 Bb

5.3 ± 0.35 Bb

5.2 ± 0.33 Bb

4.9 ± 0.37 Bb

9

8.9 ± 0.26 Aa

7.4 ± 1.06 Ba

7.4 ± 0.54 Ba

6.4 ± 0.85 Ca

6.8 ± 1.19 Ba

12

7.3 ± 0.35 Ab

7.5 ± 0.39 Aa

7.3 ± 0.19 Aa

6.7 ± 0.29 Ba

6.9 ± 0.42 Aa

Stage 3

0

4.4 ± 0.33 Ad

4.4 ± 0.34 Ac

4.6 ± 0.34 Ac

4.4 ± 0.54 Ab

4.4 ± 0.30 Ab

3

5.6 ± 0.51 Ac

5.2 ± 0.41 ABb

5.2 ± 0.34 ABbc

4.8 ± 0.14 Bb

4.9 ± 0.25 Bb

6

7.2 ± 0.49 Ab

5.3 ± 0.39 Bb

5.3 ± 0.31 Bb

4.9 ± 0.39 Bb

4.9 ± 0.28 Bb

9

8.4 ± 0.66 Aa

7.4 ± 0.99 Ba

7.2 ± 0.95 Ba

6.6 ± 0.65 Ca

6.1 ± 0.86 Ca

12

7.2 ± 0.52 ABb

7.6 ± 0.32 Aa

7.5 ± 0.44 Aa

6.7 ± 0.83 Ba

6.8 ± 0.44 Ba

Mean values in the same row (A, B) and in the same column (a, b) followed by different letters differ significantly (P < 0.05) (n = 20). Overall liking degree was evaluated on a 9 to 1 scale, where 9 = excellent, no defects, 7 = good, minor defects, 5 = fair, moderate defects, 3 = poor, major defects, 1 = unusable. A score of 6 was considered the limit of salability

A rapid increase of liking degree score in fruit on day 0 after 150-day storage was observed compared with that of fruit on day 0 after 90-day storage (Table 2). The highest score of control fruit during shelf life was 8.03, 7.79, 7.76 on day 9, 9, 6, respectively for S1, S2, S3 fruit. 1-MCP treatments reached the highest liking degree on day 9 and the highest scores of 0.5 μLL−1 and 0.75 μLL−1 during shelf life were close to control, but 1.0 μLL−1 and 1.5 μLL−1 treatments were lower than untreated fruit. All the treatments including control showed a sharp decrease on day 12.
Table 2

Overall liking score of kiwifruit during shelf life at 20 °C after 150 days storage

Ripening stage

Shelf life(days)

1-MCP Concentration (μLL−1)

Control

0.5

0.75

1.0

1.5

Stage 1

0

6.5 ± 0.26 Ac

6.6 ± 0.17 Ab

6.4 ± 0.23 Ab

6.0 ± 0.19 ABb

5.8 ± 0.22 Bb

3

7.0 ± 0.13 Ab

7.1 ± 0.17 Aab

6.9 ± 0.11 Aab

6.7 ± 0.12 Aa

6.5 ± 0.25 Aa

6

7.3 ± 0.22 Ab

7.1 ± 0.12 Aa

7.0 ± 0.30 Aa

6.9 ± 0.18 Aa

6.7 ± 0.21 Aa

9

8.0 ± 0.30 Aa

7.5 ± 0.36 Aa

7.4 ± 0.28 Aa

6.7 ± 0.21 Ba

6.5 ± 0.36 Ba

12

5.0 ± 0.33 Ad

5.6 ± 0.50 Ac

5.2 ± 0.22 Ac

5.1 ± 0.42 Ac

5.1 ± 0.35 Ab

Stage 2

0

6.7 ± 0.21 Ab

6.7 ± 0.27 Ab

6.5 ± 0.22 Ab

6.2 ± 0.14 Aa

6.1 ± 0.20 Aa

3

7.4 ± 0.35 Aa

6.9 ± 0.21 Ab

7.0 ± 0.29 Aa

6.7 ± 0.45 ABa

6.4 ± 0.23 Ba

6

7.5 ± 0.31 Aa

7.3 ± 0.22 Aab

7.2 ± 0.22 Aa

6.5 ± 0.32 Ba

6.4 ± 0.41 Ba

9

7.8 ± 0.45 Aa

7.7 ± 0.23 Aa

7.5 ± 0.31 Aa

6.7 ± 0.21 Ba

6.5 ± 0.36 Ba

12

4.4 ± 0.42 Bc

5.4 ± 0.35 Ac

5.2 ± 0.26 Ac

5.2 ± 0.23 Ab

5.1 ± 0.20 Ab

Stage 3

0

6.8 ± 0.30 Ab

6.6 ± 0.34 Ab

6.5 ± 0.15 Ab

6.3 ± 0.21 Aa

6.1 ± 0.30 Aa

3

7.1 ± 0.37 Aab

6.9 ± 0.23 ABb

6.8 ± 0.22 ABb

6.6 ± 0.35 ABa

6.4 ± 0.35 Ba

6

7.8 ± 0.23 Aa

7.5 ± 0.36 Aa

7.5 ± 0.24 Aa

6.8 ± 0.24 Ba

6.6 ± 0.27 Ba

9

7.2 ± 0.22 Aa

7.6 ± 0.33 Aa

7.5 ± 0.31 Aa

6.7 ± 0.33 Ba

6.6 ± 0.42 Ba

12

4.8 ± 0.17 Ac

5.2 ± 0.23 Ac

5.0 ± 0.23 Ac

5.2 ± 0.19 Ab

5.3 ± 0.22 Ab

Mean values in the same row (A, B) and in the same column (a, b) followed by different letters differ significantly (P < 0.05) (n = 20). Overall liking degree was evaluated on a 9 to 1 scale, where 9 = excellent, no defects, 7 = good, minor defects, 5 = fair, moderate defects, 3 = poor, major defects, 1 = unusable. A score of 6 was considered the limit of salability

The results showed that fruit liking degree was significantly suppressed by application of 1.0 or 1.5 μLL−1 1-MCP, and higher overall liking scores were obtained in fruit treated with 0.75 or 0.5 μLL−1 1-MCP, while the scores of all 1-MCP treated fruit were significantly lower than control. Harvest ripening stages with SSC from 6.42 % to 7.50 % did not influence this difference between control and 1-MCP treatment in terms of eating quality.

Firmness

The softening of 1-MCP-treated fruit harvested at all ripening stages was slowed down during 90 days cold storage and subsequent shelf life compared with the control fruit (Fig. 1, A1–C1). Fruit treated with higher 1-MCP doses up to 1.0 μLL−1 result in a higher value of fruit firmness, while firmness in fruit treated with 1.5 μLL−1 1-MCP was lower than that of fruit treated with 1.0 μLL−1 1-MCP. On day 12 of shelf life, firmness for control fruit from S1, S2 and S3 were 4.2 N, 3 N, 3.8 N respectively, and 1-MCP-treated fruit of three ripening stages showed value of from 6 N to 8 N (Fig. 1).
https://static-content.springer.com/image/art%3A10.1007%2Fs13197-013-0986-y/MediaObjects/13197_2013_986_Fig1_HTML.gif
Fig. 1

Values are Mean ± SD (n = 20). Firmness of kiwifruit harvested at 6.4 % SSC, 7.0 % SSC, 7.5 % SSC, during shelf life at 20 °C after 90 days (A1, B1, C1) and after 150 days (A2, B2, C2) storage. A stands for the kiwifruit ripening stage of 6.4 % SSC, B stands for the ripening stage of 7.0 % SSC, C stands for the ripening stage of 7.5 % SSC

Firmness in control and 1-MCP-treated fruit was maintained until day 9 during shelf life after 150-day storage (Fig. 1, A2–C2). During shelf life, control fruit of S1, S2, S3 shared a similar firmness. On day 12 of shelf life, 1-MCP-treated fruit reached the value of 4–5.5 N, 4.5–5.5 N, 4.5–5.5 N for S1, S2, S3 fruits, respectively, compared with 2–3 N for control fruit.

Firmness plays an important role in kiwifruit consumer acceptance, and the ‘eating ripe’ flesh firmness for ‘Hayward’ kiwifruit varied from previous research which consists of 3.9–7.8 N (Stec et al. 1989), 6–8 N (Paterson et al. 1991), 9–13.5 N (Crisosto and Crisosto 2001). Based on the sensory evaluation in this experiment, firmness values under 7.5 N did not suppress fruit mouthfeel and overall liking degree, and 3.5 N was considered as excessively soft. Firmness of 1-MCP treatments reached 7.5 N within 12-day shelf life, with that of the control fruit under 7.5 N from day 0 to day 12.

Soluble solids content

After 90-day cold storage, SSC rapidly increased from 6.4 %, 7.0 %, 7.5 % to 12.5–13.5 % measured on day 0 of shelf life for S1, S2, S3 fruits respectively (Table 3). No significant difference was observed among the control and 1-MCP-treated fruit or fruit treated with different 1-MCP concentrations. For all the treatments, SSC did not change obviously within 12 days shelf life following 150 days storage and there was no significant difference among 1-MCP treatments and control fruit (Table 4).

SSC values increased from 6.42 %–7.50 % at harvest to approximately 13 % before the 90th day of cold storage. Then its increase was plateaued during continued storage at 0 °C or shelf life at 20 °C. The previous research showed SSC may play a major role on consumers preferences for kiwifruit (Matsumoto et al. 1983; MacRae et al. 1990). In this experiment, there was no significant difference among control and 1-MCP-treated fruit in SSC during shelf life after 90-day or 150-day storage. Similar results were obtained in other studies (Matsumoto et al. 1983; Kim et al. 2001; Carlos et al. 2001; Colelli and Amodio 2003; Neves et al. 2003; Koukounaras and Sfakiotakis 2007). However, sensory evaluation from each treatment was different, although they shared a similar SSC mean value.

Titratable acidity

On day 0, TA values from four doses of 1-MCP treatments showed no difference but were higher than that of control fruit. During shelf life, the fruit treated with 1.0 and 1.5 μLL−11-MCP maintained the content of TA on day 0, but reduction in the control, 0.5 and 0.75 μLL−1 1-MCP-treated fruit were observed, with a slightly higher TA value in 0.5 and 0.75 μLL−1 1-MCP-treated fruit compared with control fruit at each evaluation, for each ripening stage (Table 5). Control fruits from ripening stages of S1, S2, S3 reached TA value of 1.20–1.25 % on day 6, 6, 9 respectively, but no 1-MCP-treated fruit attained the above value.
Table 3

Soluble solids content of kiwifruit during shelf life at 20 °C after 90 days storage

Ripening Stage

Shelf life(days)

1-MCP Concentration (μLL−1)

Control

0.5

0.75

1.0

1.5

Stage 1

0

13.1 ± 0.46Aa

12.6 ± 0.45Aa

12.8 ± 0.38Ab

13.2 ± 0.26Ab

12.8 ± 0.82Aa

3

13.1 ± 0.64Aa

12.4 ± 0.69Ba

13.2 ± 0.56Aab

13.2 ± 0.52Ab

12.7 ± 0.51ABa

6

12.6 ± 0.56Ba

12.6 ± 0.61Ba

13.0 ± 0.64Bab

13.6 ± 0.65Aa

13.1 ± 0.75Ba

9

12.8 ± 0.55Ba

12.6 ± 0.45Ba

13.4 ± 0.49Aa

13.0 ± 0.48ABb

13.0 ± 0.30ABa

12

13.0 ± 0.62Aa

12.4 ± 0.61Ba

12.5 ± 0.41ABb

12.9 ± 0.39Ab

12.9 ± 0.56Aa

Stage 2

0

13.3 ± 0.59Ab

12.6 ± 0.26Ba

13.4 ± 0.54Aa

12.7 ± 0.10Ba

12.8 ± 0.38Bb

3

13.5 ± 0.40Aab

12.8 ± 0.57BCa

13.2 ± 0.43ABa

12.3 ± 0.46Ca

13.1 ± 0.48ABab

6

13.9 ± 0.38Aa

12.4 ± 0.75BCa

13.2 ± 0.57Ba

12.3 ± 0.65Ca

12.9 ± 0.44Bb

9

13.8 ± 0.37Aa

12.7 ± 0.62Ba

13.3 ± 0.27ABa

12.9 ± 0.44Ba

13.5 ± 0.42Aa

12

13.4 ± 0.35Aab

12.7 ± 0.85Ba

13.4 ± 0.41Aa

12.7 ± 0.53Ba

13.6 ± 0.37Aa

Stage 3

0

12.8 ± 0.41Aab

12.7 ± 0.53Aa

12.5 ± 0.62Ab

12.7 ± 0.43Aa

12.8 ± 0.74Aa

3

13.0 ± 0.62Aa

13.1 ± 0.57Aa

13.3 ± 0.42Aa

13.1 ± 0.29Aa

12.7 ± 0.43Aa

6

13.0 ± 0.71ABa

13.1 ± 0.45ABa

13.4 ± 0.83Aa

13.1 ± 0.54ABa

12.8 ± 0.80Ba

9

12.5 ± 0.44Bb

12.9 ± 0.36ABa

12.7 ± 0.57ABb

13.1 ± 0.42Aa

13.1 ± 0.54Aa

12

12.6 ± 0.68Aab

12.8 ± 0.51Aa

12.5 ± 0.52Ab

13.0 ± 0.37Aa

12.6 ± 0.56Aa

Mean values in the same row (A, B) and in the same column (a, b) followed by different letters differ significantly (P < 0.05) (n = 20)

At shelf life day 0 after 150-day storage, a rapid decrease of TA value occurred in control and 0.5 and 0.75 μLL−1 1-MCP-treated fruit from S1, S2, S3 stages, and 1.0 and 1.5 μLL−11-MCP-treated fruit from S3 stage during cold storage (Table 6). Control fruit of S1 and S2 achieved the TA value of 1.20–1.25 % on day 6, while control fruit from S3 fruit showed a TA value of lower than 1.25 % from day 0 to day 12. Significant difference of TA content between control and 1-MCP-treated fruit was observed during shelf life for all ripening stages, and TA value in 0.5 and 0.75 μLL−1 1-MCP-treated fruit was significantly lower than value of fruit treated with 1.0 and 1.5 μLL−1 1-MCP.
Table 4

Soluble solids content of kiwifruit during shelf life at 20 °C after 150 days storage

Ripening Stage

Shelf life(days)

1-MCP Concentration (μLL−1)

Control

0.5

0.75

1.0

1.5

Stage 1

0

12.7 ± 0.31ABb

12.5 ± 0.61ABb

13.0 ± 0.25Aa

12.7 ± 0.78ABa

12.3 ± 0.63Bb

3

12.6 ± 0.31Bb

12.4 ± 0.41Bb

13.1 ± 0.56Aa

13.0 ± 0.45Aa

12.5 ± 0.48Bab

6

13.4 ± 0.60Aa

13.0 ± 0.49Aab

13.3 ± 0.74Aa

12.5 ± 0.56Ba

12.9 ± 0.72ABab

9

12.9 ± 0.56Aab

12.6 ± 0.45Ab

12.9 ± 0.54Aa

12.5 ± 0.49Aa

13.0 ± 0.60Aa

12

13.1 ± 0.26Aa

13.4 ± 0.50Aa

12.9 ± 0.51Aa

12.6 ± 0.34Ba

12.8 ± 0.32Aab

Stage 2

0

13.0 ± 0.46Abc

13.5 ± 0.65Aa

13.2 ± 0.95Ab

13.6 ± 0.61Aa

13.6 ± 0.34Aa

3

13.1 ± 0.70Abc

13.7 ± 0.57Aa

13.5 ± 0.63Aab

13.7 ± 0.62Aa

13.6 ± 0.41Aa

6

12.7 ± 0.41Bc

13.7 ± 0.41Aa

14.0 ± 0.72Aa

12.9 ± 0.34Bb

13.8 ± 0.37Aa

9

13.6 ± 0.63Ab

12.9 ± 0.32Bb

12.6 ± 0.47Bc

12.9 ± 0.57Bb

13.6 ± 0.61Aa

12

14.7 ± 0.14Aa

13.1 ± 0.63Cab

13.9 ± 0.80Ba

14.0 ± 0.26Ba

14.0 ± 0.35Ba

Stage 3

0

13.0 ± 0.64Aab

12.9 ± 0.55Aa

13.0 ± 0.87Aa

12.7 ± 0.64Aa

12.7 ± 0.13Ab

3

13.1 ± 0.49Aab

12.8 ± 0.33Aa

12.7 ± 0.56Aa

12.8 ± 0.36Aa

12.6 ± 0.72Ab

6

12.6 ± 0.49Ab

12.8 ± 0.43Aa

13.1 ± 0.52Aa

13.0 ± 0.59Aa

13.1 ± 0.50Aab

9

12.6 ± 0.41Ab

12.8 ± 0.52Aa

13.1 ± 0.58Aa

13.3 ± 0.56Aa

12.9 ± 0.79Ab

12

13.4 ± 0.85Aa

13.2 ± 0.89Aa

13.3 ± 0.45Aa

13.3 ± 0.26Aa

13.6 ± 0.62Aa

Mean values in the same row (A, B) and in the same column (a, b) followed by different letters differ significantly (P < 0.05) (n = 20)

Acidity affects consumer acceptance for kiwifruit (McMath et al. 1991; Marsh et al. 2004). According to the sensory evaluation in this experiment, excess sourness was the primary attribute to lower the fruit liking degree of fruit treated with 1-MCP. Fruit liking degree was negatively correlated with TA content, and high 1-MCP concentration accompany by high TA content. Fruit treated with 1.0 or 1.5 μLL−1 1-MCP showed significant higher TA value than other treatments. Previous research showed that TA values were affected or not affected by application of 1-MCP on kiwifruit (Kim et al. 2001; Colelli and Amodio 2003; Neves et al. 2003; Boquete et al. 2004), and other fruits treated with 1-MCP also revealed a mixed result (Blankenship and Dole 2003).

Fruit decay

With exception of slightly higher value in S1 control fruit, fruit decay was under 20 % during 0 °C, without significant difference among control and 1-MCP treated fruit after 90 days storage (Table 7). After fruit transferred to 20 °C, 1-MCP-treated fruit of S2 and S3 showed a lower decay compared with control fruit.
Table 5

Titratable acidity of kiwifruit during shelf life at 20 °C after 90 days storage

Ripening stage

Shelf life(days)

1-MCP Concentration (μLL−1)

Control

0.5

0.75

1.0

1.5

Stage 1

0

1.35 ± 0.03Ba

1.47 ± 0.04Aa

1.47 ± 0.05Aa

1.47 ± 0.05Aa

1.47 ± 0.05Aab

3

1.33 ± 0.03Ca

1.44 ± 0.04Ba

1.48 ± 0.01ABa

1.50 ± 0.01ABa

1.53 ± 0.01Aa

6

1.25 ± 0.04Db

1.35 ± 0.05Cb

1.42 ± 0.03Ba

1.47 ± 0.03ABa

1.50 ± 0.01Aa

9

1.20 ± 0.07Cb

1.35 ± 0.04Bb

1.36 ± 0.04Bb

1.46 ± 0.04Aab

1.45 ± 0.03Ab

12

1.20 ± 0.04Cb

1.29 ± 0.03Bb

1.35 ± 0.04Bb

1.41 ± 0.05ABb

1.44 ± 0.03Ab

Stage 2

0

1.40 ± 0.06Ba

1.46 ± 0.04ABa

1.47 ± 0.05Aa

1.51 ± 0.03Aa

1.51 ± 0.03Aa

3

1.34 ± 0.03Cb

1.46 ± 0.01Ba

1.47 ± 0.02ABa

1.53 ± 0.04Aa

1.54 ± 0.02Aa

6

1.22 ± 0.02Cc

1.33 ± 0.05Bb

1.36 ± 0.01Bb

1.46 ± 0.04Ab

1.45 ± 0.04Ab

9

1.23 ± 0.05Dc

1.36 ± 0.02Cb

1.39 ± 0.01Cb

1.42 ± 0.03Bb

1.49 ± 0.02Ab

12

1.19 ± 0.06Dc

1.29 ± 0.04Bb

1.29 ± 0.03Bd

1.38 ± 0.02Ac

1.43 ± 0.03Ab

Stage 3

0

1.41 ± 0.02Ca

1.46 ± 0.04Ba

1.47 ± 0.02Ba

1.50 ± 0.02ABa

1.53 ± 0.04Aa

3

1.43 ± 0.04Ba

1.44 ± 0.04Ba

1.45 ± 0.04Ba

1.48 ± 0.08ABa

1.50 ± 0.01Aa

6

1.30 ± 0.01Cb

1.45 ± 0.04Ba

1.47 ± 0.02Ba

1.41 ± 0.01Bb

1.51 ± 0.02Aa

9

1.23 ± 0.04Cc

1.38 ± 0.02Bb

1.40 ± 0.04Bb

1.48 ± 0.02Aa

1.48 ± 0.02Aa

12

1.22 ± 0.10Dc

1.32 ± 0.02Cc

1.35 ± 0.02Cb

1.43 ± 0.03Bab

1.50 ± 0.02Aa

Mean values in the same row (A, B) and in the same column (a, b) followed by different letters differ significantly (P < 0.05) (n = 20). Titratable acid was determined by titration with 0.1 N NaOH to pH 8.2 and expressed as citric acid

Fruit decay after 150 days storage was significantly higher than that of 90-day storage, and the incidence of control fruit was much more severe than 1-MCP-treated fruit, either after 150 days cold storage or subsequent 12 days shelf life (Table 7). After cold storage for 150 days, decay incidence of 1-MCP-treated fruit was 9–23 %, while 33–40 % for control fruit. For all treatments, a rapid increase of decay incidence was observed during shelf life.
Table 6

Titratable acidity of kiwifruit during shelf life at 20 °C after 150 days storage

Ripening stage

Shelf life(days)

1-MCP Concentration (μLL−1)

Control

0.5

0.75

1.0

1.5

Stage 1

0

1.29 ± 0.02Ba

1.32 ± 0.01Ba

1.32 ± 0.01Ba

1.43 ± 0.01Aa

1.45 ± 0.03Aa

3

1.30 ± 0.02Ba

1.32 ± 0.01Ba

1.31 ± 0.01Ba

1.42 ± 0.01Aa

1.44 ± 0.01Aa

6

1.20 ± 0.02Cb

1.33 ± 0.01Ba

1.34 ± 0Ba

1.42 ± 0.03Aa

1.41 ± 0.01Aab

9

1.20 ± 0.01Cb

1.31 ± 0.02Ba

1.33 ± 0.02Ba

1.39 ± 0.01Aa

1.39 ± 0.01Ab

12

1.12 ± 0.02Cc

1.23 ± 0.02Bb

1.24 ± 0.02Bb

1.30 ± 0.02Ab

1.30 ± 0.02Ac

Stage 2

0

1.31 ± 0.02Ba

1.36 ± 0Ba

1.40 ± 0.02Aa

1.42 ± 0.01Aa

1.42 ± 0.02Aa

3

1.32 ± 0.03Ba

1.36 ± 0.02ABa

1.40 ± 0.02Aa

1.42 ± 0.03Aa

1.42 ± 0.01Aa

6

1.24 ± 0.01Cb

1.37 ± 0.01Ba

1.38 ± 0.01Ba

1.43 ± 0.01Aa

1.43 ± 0.01Aa

9

1.20 ± 0.01Cb

1.31 ± 0.01Bb

1.33 ± 0.02Bb

1.40 ± 0.01Aa

1.39 ± 0.01Ab

12

1.12 ± 0.01Bc

1.25 ± 0.02Ac

1.26 ± 0.02Ac

1.30 ± 0.01Ab

1.29 ± 0.01Ac

Stage 3

0

1.18 ± 0.01Cb

1.25 ± 0Ba

1.28 ± 0.02Ba

1.33 ± 0.01Aa

1.39 ± 0.01Aa

3

1.21 ± 0.02Ca

1.26 ± 0.01Ba

1.28 ± 0.01Ba

1.32 ± 0.01Aa

1.37 ± 0.01Aa

6

1.22 ± 0.01Ca

1.25 ± 0.01Ba

1.27 ± 0.03Ba

1.33 ± 0.01Aa

1.38 ± 0.02Aa

9

1.21 ± 0.01Ca

1.24 ± 0.01Ba

1.24 ± 0.01Ba

1.30 ± 0.01Aa

1.26 ± 0.01Bb

12

1.12 ± 0.01Bc

1.14 ± 0.01Bb

1.13 ± 0.01Bb

1.21 ± 0.01Ab

1.22 ± 0.01Ab

Mean values in the same row (A, B) and in the same column (a, b) followed by different letters differ significantly (P < 0.05) (n = 20). Titratable acid was determined by titration with 0.1 N NaOH to pH 8.2 and expressed as citric acid

Table 7

Decay incidence (%) of kiwifruit during shelf life at 20 °C after 90 and 150 days storage

Ripening stage

Temperature

1-MCP Concentration (μLL−1)

Control

0.5

0.75

1.0

1.5

After 90 days

  Stage 1

0 °C

21 a

13 b

16 b

11 b

14 b

20 °C

7 b

13 a

10 a

13 ab

13 a

  Stage 2

0 °C

15 a

15 a

14 a

17 a

13 a

20 °C

23 a

13 b

13 b

11 b

10 b

  Stage 3

0 °C

15 a

13 a

11 a

12 a

17 a

20 °C

60 a

10 b

17 b

13 b

10 b

After 150 days

  Stage 1

0 °C

33 b

14 c

15 c

17 c

58 a

20 °C

80 a

32 b

27 b

38 b

34 b

  Stage 2

0 °C

40 a

9 c

15 c

23 b

12 c

20 °C

83 a

33 c

31 c

30 c

43 b

  Stage 3

0 °C

38 a

17 b

22 b

23 b

26 b

20 °C

90 a

30 c

47 b

39 c

42 bc

Mean values in the same column (a, b) followed by different letters differ significantly (P < 0.05) (n = 20). Fruit with symptoms of soft rot flesh or visible mold on surface was recognized as decayed one

Conclusions

In this study, fruit liking degree was significantly suppressed by application of 1.0 or 1.5 μLL−1 1-MCP, and higher overall liking scores were obtained in fruit treated with 0.75 or 0.5 μLL−1 1-MCP, while the scores of all 1-MCP treated fruit were significantly lower than control. Harvest ripening stages with SSC from 6.42 % to 7.50 % did not influence this difference between control and 1-MCP treatment in terms of eating quality. Although firmness was higher in fruit treated with 1-MCP, it did not significantly lower the overall liking degree. Application of 1-MCP did not influence SSC value after 90 or 150 days storage or during subsequent shelf life. Excessive sourness was the main factor affecting fruit eating quality. It must be noted that some 1-MCP treated fruit did not full ripe when they was assessed on day 12 during shelf life, but high sourness and low firmness was observed in 1-MCP treated fruit in extended shelf life. It showed that even if 1-MCP treated fruit get soft, kiwifruit still contained high titratable acidity. However, it should be noted that sensory evaluation was conducted on fruit without decay one. Decay incidence in control fruit of S1 after 12 days shelf life following 90-day storage showed no difference from that of 1-MCP-treated fruit, but higher decay control fruit was observed from S2 and S3, and after 150 day- storage or subsequent 12 day shelf life, control fruit showed 33–40 % or 80–90 % decay incidence respectively, which was significantly higher than that of 1-MCP-treated fruit and destroyed the vendibility of kiwifruit. Our research suggested that application of 1-MCP is not necessary for ‘Qinmei’ kiwifruit harvested at S1 ripening stage with an anticipation of 90-day storage. However, it showed the necessity of utilization of 1-MCP for 150 days cold storage and higher ripening stage fruit for 90 days cold storage.

Copyright information

© Association of Food Scientists & Technologists (India) 2013