METHOD FOR PREDICTING SHELF LIFE AND QUALITY OF FRUITS OR VEGETABLES

Abstract

A method for predicting the quality and shelf life of fruits or vegetables includes: recording ambient temperatures of the fruits or vegetables continuously using a temperature recorder from the beginning of plucking the fruits or vegetables and throughout entire supply chain including harvesting, grading, storage, transport and shelf period, determining an effective accumulated temperature value of the fruits during the entire supply chain, and predicting marketable fruit rate and nutritional quality of the fruits based on the effective accumulated temperature value. The marketable fruit rate, firmness and vitamin C content negatively correlate with the accumulated temperature value, and thus it is possible to predict the marketable fruit rate and storage quality of fruits based on the effective accumulated temperature values of the fruits or vegetables during the post-harvest storage and shelf period.

Claims

1. A method for predicting a quality of fruits, comprising: recording ambient temperatures of the fruits continuously by using a temperature recorder from a beginning of plucking the fruits or vegetables and throughout an entire supply chain comprising harvesting, grading, storage, transport and shelf period, determining an effective accumulated temperature value of the fruits during the entire supply chain, and predicting a marketable fruit rate and a nutritional quality of the fruits based on the effective accumulated temperature value.

2. The method according to claim 1, wherein the fruits are litchis, and the effective accumulated temperature value during the entire supply chain is lower than or equal to 1,200° C..Math.h or 50° C..Math.day.

3. The method according to claim 1, wherein the fruits are litchis, wherein the marketable fruit rate and a vitamin C content in a pulp negatively correlate with the effective accumulated temperature value.

4. The method according to claim 1, wherein the fruits are fresh goji berries, and the effective accumulated temperature value during the entire supply chain is lower than or equal to 60° C..Math.day.

5. The method according to claim 1, wherein the fruits are fresh goji berries, wherein the marketable fruit rate and a firmness negatively correlate with the effective accumulated temperature value, while a zeaxanthin content positively correlates with the effective accumulated temperature value.

6. The method according to claim 1, further comprising a step of maintaining the effective accumulated temperature value during the entire supply chain lower than or equal to a predetermined value so that the fruits have the marketable fruit rate ≥95%.

7. The method according to claim 6, wherein the fruits are litchis and the predetermined value is 1,200° C..Math.h or 50° C..Math.day.

8. The method according to claim 6, wherein the fruits are fresh goji berries and the predetermined value is 60° C..Math.day.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 shows the correlations between the marketable fruit rates and the accumulated temperature values of litchis “Gui-Wei” and “Nuo-Mi-Ci” in embodiment 1 with cold chain transport and a shelf period of 3 days under ordinary temperature.

[0015] FIG. 2 shows the changes in fruit appearance and total soluble solids (TSS) content in pulp of litchis “Gui-Wei” and “Nuo-Mi-Ci” in embodiment 1 with cold chain transport and a shelf period of 3 days under ordinary temperature.

[0016] FIG. 3 shows the correlations between the marketable fruit rates and the accumulated temperature values of litchis “Huai-Zhi” and “Nuo-Mi-Ci” in embodiment 1 with ordinary-temperature transport and a shelf period of 3 days under ordinary temperature.

[0017] FIG. 4 shows the change in vitamin C (Vc) content in pulp of litchis “Huai-Zhi” in embodiment 1 with ordinary-temperature transport and a shelf period of 3 days under ordinary temperature.

[0018] FIG. 5 shows the correlations between the marketable fruit rates and the accumulated temperature values of litchis in embodiment 1 when litchi varieties and transport types are comprehensively considered.

[0019] FIG. 6 shows the correlations between the marketable fruit rates and the accumulated temperature values of fresh goji berries in embodiment 2.

[0020] FIG. 7 shows the correlations between the fruit firmness and the accumulated temperature values of fresh goji berries in embodiment 2.

[0021] FIG. 8 shows the correlations between the zeaxanthin contents and the accumulated temperature values of fresh goji berries in embodiment 2.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] The following embodiments are provided to further illustrate the present invention but not to limit the present invention.

Embodiment 1: Method for Predicting Shelf Life and Quality of Litchi Fruits

[0023] 1. Materials

[0024] Litchi varieties and degree of ripeness: Commercially harvested litchis “Gui-Wei”, “Nuo-Mi-Ci” and “Huai-Zhi”.

[0025] 2. Method

[0026] The litchis were collected from Conghua region in Guangzhou. Litchi fruits, uniform in color and size, and free from pests, diseases, mechanical damages, and defects, were selected. Ambient temperatures were recorded from the beginning of plucking the fruits. The test was performed in two groups. For group I, the litchi fruits (without leaves) were pre-cooled in ice water for 5-10 minutes until the core temperature was low than or equal to 8° C., and packed in foam boxes (5 kg in each box) wherein two ice packs and one temperature recorder were provided inside each box which was then further packed in a paper box and transported by plane; at least three replicates for each litchi variety. For group II, the litchi fruits (with leaves) were packed in paper boxes with vents wherein one temperature recorder was provided inside each box (no pre-cooling step; no ice packs), and land transported under ordinary temperature; at least three replicates for each litchi variety. After the two groups of litchi fruits arrived in the destination city, the ambient temperatures were still recorded so as to determine the marketable fruit rates and the contents of total soluble solids (TSS) and vitamin C in pulp, and then the correlations between these quality indicators and accumulated temperature value were analyzed.

[0027] 3. Results and Analysis

[0028] As shown in FIG. 1, during the cold chain transport and ordinary-temperature shelf period, the litchis “Gui-Wei” and “Nuo-Mi-Ci” exhibited negative correlations between the marketable fruit rates and the accumulated temperature values. Especially, the litchis “Gui-Wei” exhibited a significantly negative correlation between the marketable fruit rate and the accumulated temperature value, with a coefficient of correlation (R.sup.2) up to 0.997.

[0029] As shown in FIG. 2, during the cold chain transport and ordinary-temperature shelf period, the content of total soluble solids (TSS) of the litchis “Gui-Wei” increased at first but then decreased, while the TSS content of the litchis “Nuo-Mi-Ci” decreased at first but then increased. Such results indicate that, during the cold chain transport and ordinary-temperature shelf period, the TSS contents of litchis will increase or decrease without a regular pattern, and have no correlation with accumulated temperature values.

[0030] As shown in FIG. 3, during the ordinary-temperature transport and ordinary-temperature shelf period, the litchis “Huai-Zhi” and “Nuo-Mi-Ci” both exhibited negative correlations between the marketable fruit rates and the accumulated temperature values, with a coefficient of correlation (R.sup.2) of 0.947 and 0.950 respectively.

[0031] As shown in FIG. 4, during the ordinary-temperature transport and ordinary-temperature shelf period, the litchis “Huai-Zhi” exhibited a negative correlation between the vitamin C (Vc) content and the accumulated temperature value, with a coefficient of correlation (R.sup.2) of 0.947.

[0032] As shown in FIG. 5, regardless of whether it was “Gui-Zhi”, “Nuo-Mi-Ci”, or “Huai-Zhi”, and regardless of whether it was by cold chain transport or ordinary-temperature transport, the litchis exhibited a negative correlation between the marketable fruit rate and the accumulated temperature value.

[0033] It can be concluded from FIG. 1 to FIG. 5 that, for litchis, the marketable fruit rate and the Vc content negatively correlate with the accumulated temperature value, wherein the recommended accumulated temperature value is lower than or equal to 1,200° C..Math.h or 50° C..Math.day. Under a condition of the recommended accumulated temperature value, the predicted marketable fruit rate can reach 95% or more, and the quality of the litchis can be guaranteed; for example, with a temperature of 10° C. for less than 5 days or a temperature of 5° C. for less than 10 days, the litchis are guaranteed to have high quality and a predicted marketable fruit rate is ≥95%.

Embodiment 2: Method for Predicting Shelf Life and Quality of Fresh Goji Berries

[0034] 1. Materials

[0035] Fresh goji berry varieties and degree of ripeness: Commercially harvested fresh goji berries “Zhong-Ke-Lv-Chuan”.

[0036] 2. Method

[0037] Fresh goji berries were collected. Ambient temperatures were recorded from the beginning of plucking the fruits. At the day the fruits were plucked, the fruits were transported to the laboratory wherein temperature recorders were provided inside the packages. The fruits were rinsed after they arrived at the laboratory. Fruits uniform in size and free from pests, diseases, mechanical damages, and defects, were selected. The selected fruits were air dried and then randomly put in plastic lunch boxes, 150 g in each box, totally ten boxes, which were then stored at 4° C. in a cold storage. The fruits were sampled every tree days for recording firmness, and sampled every week for determining marketable fruit rate and zeaxanthin content, wherein the zeaxanthin content was measured by high performance liquid chromatography (HPLC). In the end, the correlations between accumulated temperature value and various quality indicators such as marketable fruit rate, firmness and zeaxanthin content are analyzed.

[0038] 3. Results and Analysis

[0039] As shown in FIG. 6, the fresh goji berries exhibited a negative correlation between the marketable fruit rate and the accumulated temperature value, with a coefficient of correlation (R.sup.2) of 0.943.

[0040] As shown in FIG. 7, the fresh goji berries exhibited a significantly negative correlation between the fruit firmness and the accumulated temperature value, with a coefficient of correlation (R.sup.2) of 0.971.

[0041] As shown in FIG. 8, the fresh goji berries exhibited a significantly positive correlation between the zeaxanthin content and the accumulated temperature value, with a coefficient of correlation (R.sup.2) of 0.977.

[0042] It can be concluded from FIG. 6 to FIG. 8 that, for fresh goji berries, the marketable fruit rate and the firmness negatively correlate with the accumulated temperature value, while the zeaxanthin content positively correlates with the accumulated temperature value, wherein the recommended accumulated temperature value is lower than or equal to 60° C..Math.day. Under a condition of the recommended accumulated temperature value, the predicted marketable fruit rate can reach 95% or more, and the quality of the fresh goji berries can be guaranteed; for example, with a temperature of 10° C. for less than 6 days or a temperature of 6° C. for less than 10 days, the fresh goji berries are guaranteed to have high quality and a predicted marketable fruit rate is ≥95%.