26 research outputs found
The despoilers; stories of the North Dakota grain fields,
No full textChapters one and two were published in 1918 under the title "The psychology of suspicion." cf. Foreword.Mode of access: Internet
Improvement of Handling Techniques for Export of 'Kaohsiung No.11', 'Jin-Tao', and 'Zhong-Yue' Taiwan Jujube (Ziziphus mauritiana Lamk.) Fruits
No full textTaiwan jujube fruit is very perishable and it has short storage life under room temperature. The aim of this study is to investigate what essential factors influence changes in quality attributesof cv. 'Kaohsiung No. 11', 'Jin-Tao' and 'Zhong-Yue' (Z. mauritiana Lamk.) Taiwan jujube fruits. Those essential factors to be investigated are as follows: low temperature, precooling treatment, specific gravity, packaging, storage temperature and harvest date.
In maturity stage 2 (commercial stage) jujube fruit cv. 'Jin-Tao' had the highest respiration rate and ethylene production on day 3 under storage of 25°C (119.0 ml CO2 kg-1 hr-1 and 24.4 μl C2H4 kg-1 hr-1 respectively), and those which were stored at 10°C and at 5°C could be kept in cold storage until day 6. Meanwhile fruit cultivar 'Kaohsiung No.11' had the highest respiration rate and ethylene production on day 5 under storage of 25°C (13.46 ml CO2 kg-1 hr-1 and 0.96 μl C2H4 kg-1 hr-1 respectively), and 'Zhong-Yue' had the highest respiration rate and ethylene production on day 3 under storage of 25°C (24.96 ml CO2 kg-1 hr-1 and 2.33 μl C2H4 kg-1 hr-1 respectively), then both of them could maintain their shelf-life until day 13 under storage of 10°C and 5°C.
Specific gravity of jujube fruits was investigated by using pure water. The percentages of floating fruits, on the distilled water, of cv. 'Kaohsiung No. 11', 'Jin-Tao' and 'Zhong-Yue' with specific gravity < 1 were 99%, 98.4% and 90% respectively. There was no correlation among specific gravity total soluble solids and fruit firmness. Neither was total soluble solids and peel color.
In the packaging experiment, by using polyethylene bags (PE bags) or foam nets for packing jujube fruits of all cultivars, regardless of storage at 5°C or 1°C, their quality was significantly affected, especially with PE bags. During storage, fruits which were packed in foam nets were striking in weight loss.
Under precooling or no precooling condition, field heat of fruits cv. 'Zhong-Yue' could be reduced to 1°C, but that of cv. 'Jin-Tao' and 'Kaohsiung No.11' could be done to the only minimum temperature of 5°C. All fruit cultivars could be stored until day 21, afterward they were of very poor quality. So at day 21 it was quite clear that fruits which were stored at 1o C from the start with either precooling or no precooling treatment had the lowest percentage of weight loss and could maintain their peel color, fruit firmness and total soluble solids.
As for storage temperature under simulated shelf-life, the simulated shelf-life at 3°C yielded the best storage result of fruits cultivar 'Kaohsiung No. 11'. They maintained fruit quality and suffered the least chilling injury symptoms. Meanwhile fruits cultivar 'Jin-Tao' under simulated shelf-life at 3°C, 5°C, 10°C, and 15°C were found that there was no much difference in fruit quality and no chilling injury symptoms were apparent.
In addition, there was no much difference in fruit quality between fruits which were harvested in the different period of time. Fruits cultivar 'Kaohsiung No. 11' could be stored until day 21, afterward they suffered severe chilling injury symptoms and their best harvest time was March 6th, 2015. Meanwhile best harvest time of fruits cultivar 'Jin-Tao' was February 13th, 2015 and they could maintain their quality until the end of storage.
These results show that PE bags under low temperature conditioning can maintain the quality of fruit during storage and transportation. So it is possible to be another management model for commerce.台灣棗在室溫下具有容易腐爛及櫥架壽命較短的特性。本研究目的為調查影響台灣棗(Z. mauritiana Lamk. cv.'高雄11號'、'金桃'和'中葉')果實品質的重要因素，例如:低溫、比重、包裝材質、預冷處理、貯藏溫度及採收時間。
第二階段成熟度(商業成熟度)之'金桃'棗子眝藏在250C3天具有最高的呼吸率(119.0 ml CO2 kg-1 hr-1)以及乙烯高峰(24.4 μl C2H4 kg-1 hr-1)。而且，當'高雄11號' 棗子眝藏在10°C和5°C有6天儲架壽命。'高雄11號' 棗子 在250C5天有最高的呼吸率(13.46 ml CO2 kg-1 hr-1)以及乙烯高峰(0.96 μl C2H4 kg-1 hr-1)而'中葉' 棗子在250C3天產生最高的呼吸率(24.96 ml CO2 kg-1 hr-1)以及乙烯高峰(2.33 μl C2H4 kg-1 hr-1)。除此以外，'高雄11號'和'中葉' 棗子眝藏在10°C和5°C下有13天眝架壽命。比重調查結果顯示'高雄11號'、'金桃'及'中葉'果實比重小於1的比例分別為99%、98.4%和90%，而果實比重與可溶性固形物、硬度之間無顯著相關，果皮顏色與可溶性固形物間亦無明顯關係。不同包裝材質以打孔PE袋處理的果實貯藏品質較佳，其失重率明顯低於疏果網包裝，而台灣棗經1℃及5℃低溫貯藏，兩溫度處理在貯藏品質上並無明顯差異。台灣棗預冷試驗結果顯示，'中葉'果實經預冷後可降至1℃，而'金桃'和'高雄11號'僅能降至5℃。在1℃貯藏期間，有預冷及無預冷處理果實均能維持較佳的果皮顏色、果實硬度、可溶性固形物及較低的失重率，所有品種經1℃貯藏21天後其品質均逐漸降低，有無預冷處理並沒有顯著影響。模擬不同櫥架溫度試驗結果，'高雄11號'最佳貯藏溫度為3℃，能維持較好的果實品質且降低寒害症狀，'金桃'品種在3、5、10及15℃貯藏溫度對果實品質及寒害症狀並無顯著差異。此外，不同採收時間對果實貯藏品質無明顯差異，'高雄11號'最佳採收期為2015年3月6日，果實貯藏品質能維持21天左右，'金桃'最佳採收期則為2015年2月13日，其貯藏時間可長達24天。綜合以上結果，台灣棗在貯運過程中以低溫條件配合打孔PE袋包裝進行貯藏，可以維持較好的果實品質，可作為另外一種商業管理作業之參考。Contents
Page
Chinese Summary.................................i
English Summary.................................ii
Contents........................................iv
List of Tables..................................vi
List of Figures.................................viii
Chapter 1: Introduction.........................1
Chapter 2: Literature review....................2
2.1 Taiwan's jujube fruits and Indian
jujube fruits...........................2
2.2 Chilling injury and storage
conditions of jujube fruits.............3
2.3 Precooling..........................8
2.4 Postharvest bagging fruits..........10
2.5 Specific gravity....................11
2.6 Physiological changes during
ripening............................12
Chapter 3: Materials and methods................17
3.1 Plant materials.....................17
3.2 Experimental treatments.............17
3.3 Measurement of fruit
physicochemical properties..........20
3.4 Statistical analysis................21
Chapter 4: Results..............................24
4.1 Respiration rate and ethylene
production rate.....................24
4.2 Specific gravity....................32
4.3 Different packaging (PE bags and
foams nets) during storage..........37
4.4 Hydrocooling........................49
4.5 Harvest dats........................62
4.6 Different storage temperature
under simulated shelf-life..........70
Chapter 5: Discussion...........................77
5.1 Respiration rate and ethylene
production rate.....................77
5.2 Specific gravity (SG)...............78
5.3 Different packaging (PE bags
and foams nets) during storage......78
5.4 Hydrocooling........................80
5.5 Harvest date........................81
5.6 Different storage temperature
under simulated shelf-life..........81
Chapter 6: Conclusion...........................83
References......................................84
List of Tables
Table Title Page
1 Effects of specific gravity..............33
2 Effects of temperature and packaging
on fruit firmness, total soluble solids
(TSS), percentage of weight loss and
chilling injury index of 'Kaohsiung
No.11' jujube fruit......................38
3 Effects of temperature and packaging
on peel coloration of 'Kaohsiung No.11'
jujube fruits............................39
4 Effects of temperature and packaging on
fruit firmness, total soluble solids
(TSS), percentage of weight loss and
chilling injury index of 'Jin-Tao'
jujube fruit.............................41
5 Effects of temperature and packaging
on peel coloration of 'Jin-Tao' jujube
fruits...................................42
6 Effects of temperature and packaging
on fruit firmness, total soluble solids
(TSS), percentage of weight loss and
chilling injury index of 'Zhong-Yue'
jujube fruits............................44
7 Effects of temperature and packaging
on peel coloration of 'Zhong-Yue'
jujube fruits............................45
8 Effects of temperature and hydrocooling
on fruit firmness, total soluble solids
(TSS), percentage of weight loss and
chilling injury index of 'Kaohsiung
No.11' jujube fruits.....................51
9 Effects of temperature and hydrocooling
on peel coloration of 'Kaohsiung No.11'
jujube fruits............................52
10 Effects of temperature and hydrocooling
on fruit firmness, total soluble solids
(TSS), percentage of weight loss and
chilling injury index of 'Jin-Tao'
jujube fruits............................54
11 Effects of temperature and hydrocooling
on peel coloration of 'Jin-Tao' jujube
fruits...................................55
12 Effects of temperature and hydrocooling
on fruit firmness, total soluble solids
(TSS), percentage of weight loss and
chilling injury index of 'Zhong-Yue'
jujube fruits............................57
13 Effects of temperature and hydrocooling
on peel coloration of 'Zhong-Yue' jujube
fruits...................................58
14 Effects of harvest date on fruit
firmness, total soluble solids (TSS),
percentage of weight loss, and chilling
injury index of 'Kaohsiung No.11' jujube
fruits...................................63
15 Effects of harvest date on peel
coloration of 'Kaohsiung No.11'
jujube fruits............................64
16 Effects of harvest date on fruit
firmness, total soluble solids (TSS),
percentage of weight loss, and chilling
injury index of 'Jin-Tao' jujube fruits..66
17 Effects of harvest date on peel
coloration of 'Jin-Tao' jujube fruits....67
18 Effects of different storage temperature
on fruit firmness, total soluble solids
(TSS), percentage of weight loss and
chilling injury index of 'Kaohsiung
No.11' jujube fruits under simulated
shelf-life...............................71
19 Effects of different storage
temperature on peel coloration of
'Kaohsiung No.11'jujube fruits under
simulated shelf-life.....................72
20 Effects of different storage
temperature on fruit firmness, total
soluble solids (TSS), percentage of
weight loss and chilling injury index
of 'Jin-Tao' jujube fruits under
simulated shelf-life.....................73
21 Effects of different storage
temperature on peel coloration of
'Jin-Tao' jujube fruits under
simulated shelf-life.....................74
List of Figures
Figure Title Page
1 Fruits and vegetables classified
according to sensitivity to chilling
injury...................................7
2 Time sequence of events leading to
chilling injury..........................8
3 PE bags with perforations and
thickness of 0.02 mm.....................22
4 Fruits were packed in PE bags and
Foam nets................................22
5 Hydrocooling and temperature
determination............................22
6 The hedonic scale of chilling injury.....23
7 The respiration rates of 'Kaohsiung
No.11' jujube fruits.....................26
8 The ethylene production rates of
'Kaohsiung No.11' jujube fruits..........27
9 The respiration rates of 'Jin-Tao'
jujube fruits............................28
10 The ethylene production rates of
'Jin-Tao' jujube fruits..................29
11 The respiration rates of 'Zhong-Yue'
jujube fruits............................30
12 The ethylene production rates of
'Zhong-Yue' jujube fruits................31
13 Relationship between: (A) TSS and
firmness; (B) TSS and L* values; (C)
TSS and a* values; and (D) TSS and b*
values of 'Kaohsiung No. 11' jujube
fruits which floated on pure water.......34
14 Relationship between: (A) TSS and
firmness; (B) TSS and L* values; (C)
TSS and a* values; and (D) TSS and b*
values of 'Jin-Tao' jujube fruits
which floated on pure water..............35
15 Relationship between: (A) TSS and
firmness; (B) TSS and L* values; (C)
TSS and a* values; and (D) TSS and b*
values of 'Zhong-Yue' jujube fruits
which floated on pure water..............36
16 Effects of temperature and packaging
on the appearance of 'Kaohsiung No.11'
jujube fruits............................46
17 Effects of temperature and packaging
on the appearance of 'Jin-Tao' jujube
fruits...................................47
18 Effects of temperature and packaging
on the appearance of 'Zhong-Yue' jujube
fruits...................................48
19 The cooling curve of (A) 'Kaohsiung
No.11', (B) 'Jin-Tao' and (C) 'Zhong-Yue'
jujube fruit under hydrocooling..........49
20 Effects of hydrocooling and storage
temperature on the appearance of
'Kaohsiung No.11' jujube fruits..........59
21 Effects of hydrocooling and storage
temperature on the appearance of
'Jin-Tao' jujube fruits..................60
22 Effects of hydrocooling and storage
temperature on the appearance of
'Zhong-Yue' jujube fruits................61
23 Effects of harvest date on the
appearance of 'Kaohsiung No.11'
jujube fruits during storage.............68
24 Effects of harvest date on the
appearance of 'Jin-Tao' jujube
fruits during storage....................69
25 Fruits of 'Kaohsiung No. 11' jujube
were stored at 1°C for 14 days and
then at 5°C for 7 days...................75
26 Fruits of 'Kaohsiung No. 11' jujube
under simulated shelf life at 3, 5,
10, 15 and 25°C for 3 days...............75
27 Fruits of 'Jin-Tao' jujube were
stored at 1°C for 14 days and then
at 5°C for 7 days........................76
28 Fruits of 'Jin-Tao' jujube under
simulated shelf life at 3, 5, 10,
15 and 25°C for 3 days...................7
