Contribution of Active Controlled Atmosphere (CA) Technology to the Value-Chain of Perishable Fruits and to Rural Development: Case of Atemoya in Taiwan

Abstract

Atemoya is an important tropical fruit export for Taiwan, mainly produced in Taitung, a rural area of South-Eastern Taiwan. However, it was sold to virtually a single market—China—and when that market suddenly announced an import ban on the fruit in 2021, the rural farmers and the local economy were adversely affected. They had to quickly explore new overseas markets. Unfortunately, its short postharvest life makes it infeasible for long-distance transport. This study measured the impacts of the ban on the local economy using an input-output (IO) analysis. It also tested the technical feasibility of using a controlled atmosphere (CA) preservation technology, which was necessary for long-distance exports. The benefits of this strategy for the rural economy were also assessed using IO techniques. Results reveal that the atemoya value chain accounted for 2.12% of the production value, 2.75% of the value-added, and 3.62% of the employment in Taitung. Furthermore, the CA technology successfully doubled its postharvest life; thereby allowing exports to countries as far as Canada, and easing the impacts of the earlier ban. This development, together with facilitating domestic sales, boosted the local economy’s output value by NTD 491 million and its value-added by NTD 237 million. In addition, it can also increase rural employment by 2235 people. Using a smart agriculture technology in this case protected a perishable fruit industry that has a thin domestic market, from the risk of relying only on a single export destination. Consequently, this has supported the sustainability of rural communities and helped them to remain resilient.

1. Introduction

Atemoya (Annona cherimola × A. squamosa or A. squamosa × A. cherimola), an inter-species hybrid between cherimoya (A. cherimola Mill.) and sugar apple (A. squamosa L.) that was first crossbred by P. J. Wester in 1908 at the USDA’s Subtropical Laboratory in Miami, Florida [1], is one of the most important tropical fruits in Taiwan, mainly produced in Taitung because of its warm climate and little temperature variation [2]. The Chinese market opened a huge opportunity for atemoya produced in Taiwan. It became an important export fruit of Taiwan, bringing rich benefits to local farmers. However, the Chinese government announced a ban on such imports of Taiwan’s atemoya, starting mid-September 2021. This caused a substantial impact on farmers and the local economy of Taitung, so exploring new overseas markets and envisioning a strategy for the industry have become urgent issues. Unfortunately, the fruit is characterized by extremely high rates of both respiration (40–460 mg CO₂ kg^–1 hr^–1 at 20 °C) and ethylene production (100–300 μL C₂H₄ kg^–1 hr^–1 at 20 °C), a gaseous phytohormone initiating and accelerating ripening or senescence [3,4], is very susceptible to low temperatures (<10–13 °C), and has a short postharvest longevity for long distance trade [5,6]. Hence, its sale is usually restricted to domestic markets and neighboring countries. Air transport can be used but the cost makes it uncompetitive in international markets.

This study aims to measure the impacts of the import ban on Taitung’s local economy using an input-output (IO) analysis. It also tests the technical feasibility of using a controlled atmosphere (CA) preservation technology, as part of the effort to develop new export markets. The benefits of this strategy for the rural economy are also computed using IO analysis.

Due to the advancement of marine container technology in recent years, the application of CA preservation technology has extended beyond the traditional long-term storage of apples and pears, and has gradually been applied to the shipping and marketing of fresh produce. The more precise control of the environment during long-term storage helps maintain the quality and extend the postharvest life of the horticultural commodities; thereby, prolonging as well their supply period.

Through CA technology, together with the technical optimization of the pre-harvest disease management and postharvest handling, the postharvest life of atemoya was successfully extended from 1–2 to 3–4 weeks (See Section 5.1). With this technology, Taiwanese atemoya could be exported to Southeast Asia, Middle East and Canada smoothly, ameliorating the negative impacts of suddenly halting 97% of exports to a single market, such as China. This has significantly reduced the industry risk and maintained the stability in the rural communities of South-Eastern Taiwan.

The results of the input-output analysis in this study showed that the atemoya value chain accounted for 2.12% of the production value, 2.75% of the value-added, and 3.62% of the employment in Taitung (See Section 5.2). Therefore, their local economy was significantly affected by China’s ban on atemoya imports. A strategy that uses new technologies to open new export markets, together with facilitating farmers’ switch to other crops, such as the sugar apple, can cushion that impact. This can boost Taitung’s output value by NTD 491 million and its value-added by NTD 237 million. In addition, it can increase rural employment by 2235 people.

This is a successful case of applying smart agriculture in storage and transportation. By precisely controlling the environment, one can extend the post-harvest life of fresh produce and maintain their quality. The CA technology is not only useful for businesses individually but also for protecting the local economy against marketing risks in international trade. This study presents a valuable case for protecting perishable fruit industries that rely on a single export market, and which has a thin domestic market as a buffer against a global supply chain shock.

2. Atemoya Food Value Chain

Based on the export value, atemoya is the second most important fruit in Taiwan, after pineapple. In 2021, there were 2945 hectares of cultivated area, around 99% of which is in Taitung County, and about 23.8 million kg of the production (https://agr.afa.gov.tw/afa/afa_frame.jsp, accessed on 15 September 2022). Exports reached 16,392 metric tons, with a value of USD 51.8 million (https://portal.sw.nat.gov.tw/APGA/GA30, accessed on 15 September 2022). The production season of atemoya in Taiwan is from November through May of the following year, and within this period, December up to March of the following year is the peak export period. China accounted for up to 97% of the export market before they placed a ban; the rest of the export markets included Hong Kong, the United Arab Emirates and Indonesia.

Atemoya is a typical climacteric fruit, which exhibits a dramatic rise in respiration, accompanied with a burst of ethylene emission during its ripening stage, with a good storage capacity and resistance to pathogens before ripening. However, once it enters the post-ripening stage, the fruit will soften and split; it becomes intolerant to transport vibrations, and its resistance to pathogens will be drastically reduced, resulting in rapid aging and decay [4]. It is well-known that ethylene is a major factor influencing the commencement of ripening in climacteric fruits [3]. Therefore, the inhibition of the ethylene biosynthesis and its physiological reactions during storage is the key to extend the postharvest life of such fruits. Postharvest ethylene management strategies include reducing the ethylene production in the commodity itself, avoiding the accumulation of the ethylene concentration in the surrounding area, as well as inhibiting the perception and biological effects of ethylene; for example, low temperature preservation can slow down the rate of ethylene biosynthesis and actions. However, atemoya is extremely sensitive to low temperatures and susceptible to damage below the critical temperature of about 10–13 °C [5,6,7]. The current practice of using refrigerated storage technology for fresh produce does not meet the postharvest life required for long-distance marketing. Additional handling strategies other than cold preservation are required as supplements to temperature management [4]. This study investigates the viability of the CA technology in extending the storability of atemoya and allowing it to reach distant markets.

Atemoya in Taiwan is mainly for export. There are 12 operational steps inside a typical atemoya farm and packaging house [8], including harvesting, pre-cooling, collecting, sorting, cleaning, covering with mesh, grading, packing, labeling, sealing, refrigerating and loading onto the truck. The farm and packaging house will schedule the overall operation, in line with the shipment date set by the export trader. Thus, atemoya farms are involved in quality control, not only during harvest and post-harvest processing, but also in its distribution stage, which gives them a big control over a large section of the fruit’s value chain.

Taiwan’s domestic market is not sufficiently large to support the atemoya industry, and the price for which it can be sold abroad is much higher relative to the domestic price [9]. In order to increase the income of farmers and develop the rural economy, the government of Taiwan began promoting the “Atemoya Export Registration System” in 2004, to provide guidance on farm management and to standardize operations [10]. The government also encouraged exporters to sign a letter of intent with farmers’ groups to strengthen the supply chain. By 2013, ten exporters have completed registration. Earlier in 2010, atemoya was also officially included in the government’s roster for export promotion. The government also designated atemoya farms as export zones in 2011 [11]. This allowed them to receive substantial technical support from the local agricultural research and extension station of the government. They’ve also received government subsidies and benefited from several trade facilitation programs and strategies that the government organized in the previous decade. Figure 1 shows that since 2009, the export of atemoya has been rising, notwithstanding the sharp drop in 2017, both in terms of volume and value. Apart from China, exports also began to slowly expand to other new markets, such as Brunei, Bahrain, etc.

However, China announced that starting 20 September 2021, they are ceasing all imports of atemoya from Taiwan on the grounds that quarantine inspections detected several times the presence of mealybugs. This was a big blow to the industry. Farmers and exporters had to immediately find ways to sell more in existing markets and look for new ones, in order to mitigate the marketing loss. However, long-distance markets pose different regulatory and logistical challenges. For this reason, they have turned to smart agriculture for solutions to improve the situation. In particular, they sought a way to increase the post-harvest life of the produce, in order to allow exports to markets further away.

3. Active Controlled Atmosphere

Long before understanding the fundamental role played by oxygen and carbon dioxide (CO₂) on the respiration of fresh fruit and vegetables, mankind had noticed the influence of gases on their storage life. Thousands of years ago in China and Egypt, there was an ancient preservation technique of enclosing fruit and vegetables in containers or storage chambers to restrict the gas exchange, in order to extend the storage life [12]. For example, in the 8th century Tang dynasty, in order to maintain the bright red peel color and flavor of lychees, a subtropical fruit that deteriorates within 1 to 2 days under ambient air after harvest, they were sealed in hollow centers of bamboo stems with some fresh leaves during the long-distance transport [13]. Burying fruit and vegetables in the ground to preserve them is also a centuries-old practice. Romans use sealed underground pits for extending the life of certain fruits and vegetables [14]. Other examples of subterranean storage to reduce and stabilize temperatures, and modify the atmospheric gas composition include the practice of the cave storage of fruit and vegetables, as is carried out in China and Turkey, and trench storage of grains, root crops, and silage [12]. Such practices are still being observed in China for apples and pears, and in the region of Cappadocia in Turkey for citrus [12]. However, it was not until the 1800s when Berardin in France and Nyce in the United States made the first observations regarding the effect of gas on fruit ripening [14].

Based on these concepts, the first commercial apple storage adapting controlled atmosphere (CA) technique in England was constructed near Canterbury in the county of Kent, in 1929 [14,15]. CA is a preservation technique in which the gas composition of the storage environment is changed by adding or removing gases that are different from the normal atmospheric composition (20–21% oxygen, 0.03% CO₂, 78–79% nitrogen, and other trace gases), resulting in a state that benefits the quality maintenance and extending the storability of the product. Usually, the process only involves reducing the concentration of oxygen and increasing the concentration of CO₂, although sometimes, other gases, such as carbon monoxide, may also be added to the gas composition, and ethylene may also be scrubbed from the environment. The process is usually carried out in a large refrigerated gas-tight warehouse equipped with special gas generators. The concentration of constituent gases is controlled with precision, and throughout the storage process, the composition of gases inside is constantly monitored and often adjusted to maintain it at a static concentration. Although the beneficial gas composition of CA is highly specific, depending on the crop, cultivar, and field managements, the typical desired atmosphere of most fresh produce is approximately 2–5% oxygen and/or 4–5% CO₂ with 90–94% nitrogen [14,16]. Due to the low oxygen and high CO₂ inside the storage environment, not only are the respiration and ethylene emission of horticultural crops suppressed, but the microbial proliferation is also retarded; as a result, the storability of the products is enhanced.

Modification of the atmospheric composition technology for fresh produce preservation benefits include the retardation of the respiratory metabolism, ripening and senescence, some enzyme activities, oxidation, ethylene biosynthesis and its physiological reactions, vitamin loss, pest and disease development, as well as physiological disorders, such as a chilling injury [14,16].

There is a similar postharvest technique called the modified atmosphere (MA) storage, which is based on the same preservation principles, and which has also proven successful in reducing the chilling injury of fresh fruits and vegetables, such as pomegranate, banana, avocado, and mango [17]. The difference lies in the way by which the atmospheric composition is modified, and in how oxygen and CO₂ levels are adjusted. In MA storage, the gas composition inside a sealed packaging, such as microperforated polyethylene [17], is regulated by both the respiratory reaction of the commodity which reduces oxygen and increases CO₂ concentrations by naturally continuing to breathe in oxygen and exhaling CO₂, as well as by selecting a packaging material with a suitable gas permeability, to dynamically achieve the approximant optimal atmospheric environment. In other words, the gas composition during storage is controlled by the dynamic balance between the respiration of the product and the permeability of their packaging material. The major difference between CA and MA is only in the degree of control; the former is more exact [16]. It is worth noting that CA and MA technology have only been developed in recent decades and cannot be employed independent of traditional cold storage. They cannot completely replace the ordinary temperature and humidity management techniques, and should be regarded as complementary to refrigeration technology.

The demand for tropical fruits in world trade has increased in recent years, which stimulated the studies of postharvest physiology and development of technology that can handle these crops for prolonged periods. At present, the most important strategy for preserving fresh fruit and vegetables is to apply a low temperature to decrease the product metabolism and inhibit the pathological microbes. The majority of temperate fruits belong to the chilling-insensitive or chilling-tolerant category; therefore, they can be feasibly maintained in near 0–5 °C for long-term storage. Unfortunately, most tropical and subtropical native crops are sensitive to low temperatures and cannot be stored in cold conditions for a long time. Thus, they are vulnerable to chilling injury, a physiological disorder caused by the exposure to low temperatures above freezing. This strongly limits their postharvest longevity to only few weeks at the most, consequently making them highly perishable [18]. CA technology benefits tropical fruits by delaying the ripening process, reducing the ethylene synthesis and the physiological reactions, inhibiting the chilling-induced browning, as well as controlling certain diseases, physiological disorders, and pests [16,18]. It can make up for the inborn disadvantage of tropical crops’ incompatibility with cold storage; hence, it has been deemed as the most promising handling technology for the distant marketing of tropical fruits. Since CA technology, being a physical treatment, is free of chemical residues and friendly to the environment, it has a high acceptability among consumers and has attracted attention among postharvest researchers of fruit and vegetables. Therefore, CA could be a promising complementary technology to temperature management that can help prolong the marketable life of tropical fruits, especially during their marine transport [16,18].

This technology has been traditionally used for the long-term commercial storages of apples, European pears, kiwifruits, cabbages, and Chinese cabbages to ensure adequate availability for all seasons. For example, if apples are to be stored for more than 3 months, CA storage is often recommended. Moreover, the storability of avocados, bananas, cherries, grapes, mangoes, peaches, nectarines, plums, persimmons, and pomegranates may be extended to up to 3 months if CA technology is adapted.

It’s worth noting that CA technology has recently been applied in short-term storage and marine transport of fresh horticultural crops as well. This practice is mainly in order to delay ripening and to alleviate chilling injury for avocados, bananas, mangoes, melons, nectarines, papayas, peaches, plums and tomatoes; to control decay for blackberries, blueberries, cherries, figs, grapes, raspberries and strawberries; as well as to slow down senescence and undesirable compositional changes for asparaguses, broccolis, lettuces, sweet corns, fresh herbs and fresh-cut fruits and vegetables [16,19]. Interest for CA marine containers gradually increases, especially if the transit time is at or beyond the storage longevity of fresh produce in normal refrigerated air.

4. Materials and Methods

4.1. Testing the Controlled Atmosphere Technology

The experiments for this study began with small-scale laboratory trials of various storage temperatures, as well as different oxygen and CO₂ concentrations for four weeks, to assess the critical points of the chilling injury, low oxygen concentration, and high CO₂ limitations in mature-green atemoya fruit. Upon finding the suitable environmental conditions for atemoya storage, the follow-up investigations were scaled up to commercial simulation tests carried out with a CA container. Then, a pilot test in cooperation with export traders for actual marine transportation, to target markets was finally executed, in order to obtain practical feedbacks from the private sector and to optimize the CA preservation technique. Apart from simply using CA, other adjustments were carried out to ensure the feasibility of long-term export. They included the identification of pathogens that caused postharvest atemoya to rot, screening control fungicides, and integrating field and postharvest pest managements, the improvement of stress intensity and ventilation hole design of the export packaging box, as well as optimizing the cooling efficacy by using the forced-air cooling method, and the development of a small low-cost lightweight gas monitoring device that has fuel endurance.

4.2. Input-Output and Scenario Analysis

This study also used an input-output (IO) analysis to measure the contribution of atemoya in the rural economy of Taitung (output, value-added and employment) and to assess the impact thereto of exporting to new markets (Malaysia, Dubai and Canada) with the aid of CA technology. Three possible scenarios were analyzed using the IO technique, explained in Section 4.2.2.

4.2.1. Input-Output Analysis

The input-output analysis is a form of economy-wide analysis, based on the interdependencies between different economic sectors or industries. This methodology is commonly used for estimating the impacts of positive or negative economic shocks and analyzing the ripple effects throughout an economy. Input-output tables are the foundation of the IO analysis, depicting rows and columns of data that quantify the supply chain for all of the sectors of an economy.

The IO analysis can either be demand-driven or supply-sided [20]. The former is based on the original method that Leontief proposed in 1936. Changes in the final demand (consumption, investment, government) is introduced and the corresponding change in the required production output could be computed. This will be used to assess the impact of the import bans imposed by China on Taiwanese atemoya. A supply-sided IO analysis, which was pioneered by Ghosh in 1958, can be used to compute the impact of the changes in the industry supply on the overall economic system.

The solution for the change in the total output value using a demand-driven and a supply-sided IO model can be represented as Equations (1) and (2) below:

$$\mathsf{\Delta }\mathit{X}={\left(\mathit{I}-\mathit{A}\right)}^{-1}\mathsf{\Delta }\mathit{F}$$

(1)

$$\mathsf{\Delta }\mathit{X}={\left(\mathit{I}-{\mathit{B}}^{\prime }\right)}^{-1}\mathsf{\Delta }\mathit{V}$$

(2)

where $\mathit{X}$ is a column vector of final output value of good $i$; $\mathit{F}$ is a vector of the final demand (consumption, investment, government and export) for good $i$; and $\mathit{V}$ is a vector of the primary inputs including labor, capital and profits.

The ${\left(\mathit{I}-\mathit{A}\right)}^{-1}$ in Equation (1) is known as the Leontief inverse matrix, where $\mathit{I}$ is an identity matrix and $\mathit{A}$ is the matrix of technical coefficients, which are the percentage of industry $j$’s output value that comes from industry $i$’s production. In other words, it measures the amount of good $i$ required to produce one unit of good $j$. This inverse matrix has the dimensions $i\times j$, where both $i$ and $j$ represent the number of industries. Each element inside the Leontief inverse matrix represents the change in the domestic production of industry $i$ for each unit increase in the final demand for good $j$. Thus, the Leontief inverse can be used to characterize the interindustry linkages.

Moreover, the ${\left(\mathit{I}-{\mathit{B}}^{\prime }\right)}^{-1}$ in Equation (2) is the transposed Ghosh inverse matrix, where $\mathit{B}$ is the matrix of allocation or supply coefficients, which are the percentage of industry $i$’s production being allocated or supplied to industry $j$. This inverse matrix, therefore, has the same dimensions as the Leontief inverse. Each element inside the Ghosh inverse matrix, however, represents the change in the domestic supply of good $j$ for each unit increase in the primary input or value-added expenditure of industry $i.$

The total change in the output is the sum of each element in the vector $\mathsf{\Delta }\mathit{X}$, that is, ${\mathit{i}}^{\prime }\mathsf{\Delta }\mathit{X}$, where ${\mathit{i}}^{\prime }$ is a $1\times i$ row vector consisting of 1′s.

Having found the solution for $\mathsf{\Delta }\mathit{X}$, one can also solve for changes in value-added ($\mathsf{\Delta }\mathit{V}$) and change in employment ($\mathsf{\Delta }\mathit{W}$), using the Equations (3) and (4) below:

$$\mathsf{\Delta }\mathit{V}={\mathit{v}}_{\mathit{c}}\circ \mathsf{\Delta }\mathit{X}$$

(3)

$$\mathsf{\Delta }\mathit{W}=\mathit{w}\circ \mathsf{\Delta }\mathit{X}$$

(4)

where ${\mathit{v}}_{\mathit{c}}$ is a column vector of the value-added coefficients, and $\mathit{w}$ is a vector of employment coefficients. Each element inside ${\mathit{v}}_{\mathit{c}}$ represents the primary inputs of a particular industry divided by the total output of that industry, e.g., $v_{c_j}=v_j∕x_j$, where $v_j$ is the value-added in industry j, and $x_j$ is the output value of the same industry. Each element inside $\mathit{w}$ represents the amount of employment per dollar of good produced for each industry, e.g., $w_j=e_j∕x_j$, where $e_j$ is the number of employed people in industry j. Data for $e_j$ is taken from the Industry and Service Census.

4.2.2. Scenario Analysis

In order to assess the impact of opening new export markets and transforming the atemoya industry in Taitung, this study used IO analysis to examine three scenarios:

Scenario 1 evaluates the economic importance of the atemoya industry for Taitung using a supply-sided IO model. In this scenario, the study assumes that the whole NTD 2206.42 million production value of atemoya is gone and uses this as the shock to compute for the economic impact on Taitung.

Scenario 2 evaluates the impact of successfully expanding the export market through CA technology using a demand-driven IO model. The growth of exports to these new markets—Malaysia, Canada and Dubai—had to be estimated first. For Malaysia and Canada, this is achieved by first getting the per household consumption of atemoya in China, then using that statistic to derive a preliminary estimate of export possibilities to both countries. According to the statistics agencies of Malaysia and Canada, their current number of households are 7.6 million and 14.1 million, respectively (column A of

Table 1. Estimating the export growth in future trade markets.

Country	Number of Households (in ‘000) (A)	2020 Export Quantity (in ‘000 Metric Tons) (B)	Estimated Export Volume (in ‘000 Metric Tons) (C = A × 0.0491)	Weight Adjustments (D)	Change in Export Volume (in ‘000 Metric Tons) (E = (C × D) − B)	2020 Export Price (USD) (F)	Increase in Export Value (Million NTD) (G = E × F × 28/1000)
Malaysia	7600	23	373.16	0.4197	133.62	4.17	15.60
Canada	14,100	87	692.31	0.2190	64.62	2.44	4.41
Dubai							15.36
Total							35.37

). Based on the export volume data of Taiwan in 2020, the ratio of Taiwan’s atemoya exports to China per household is 0.0491 (13,588 thousand metric tons/276.95 million households), which is then used to multiply with column A to obtain a future target of successfully developing the atemoya market in Malaysia and Canada (column C). Since there are some differences between China and the other two countries, in terms of dietary habits and population composition, this initial estimate still needs to be adjusted (column D). According to the consumer survey conducted in Malaysia in early 2020, about 41.97% of those who have tasted Taiwanese atemoya for the first time indicated that they were willing to buy it. This proportion is used as a weight to adjust the estimated export volume for Malaysia. As for Canada, due to COVID-19, a similar survey could not be conducted; but based on their interview with exporters, the current market in Canada for similar types of fruit is still dominated by Chinese consumption. Therefore, the percentage of Chinese in Canada, which is about 21.9%, is used as the adjustment weight. In column E, the estimated change in export volume is computed by deducting the actual export volume to both countries in 2020 from the target export volume to Malaysia and Canada. This is subsequently multiplied by the export unit price (column F) for both countries in 2020 to obtain the change in value of the final demand (column G). As for Dubai, which is a completely new market, importers estimate that they can sell about one container (or 11.52 metric tons of atemoya) every ten days. Given the duration of the atemoya export season, there can be equivalent to 11 shipments a year. With the export unit price at USD 4330 per metric ton in 2021, the export value is estimated to be NTD 15.36 million (11.52 tons × 11 shipments × USD 4330 × 28/1,000,000) for Dubai. The sum of all three will be the shock for scenario 2.

Scenario 3 assumes that (a) the portion of planted area for atemoya equivalent to the amount previously exported to China in 2020 is to be converted to sugar apple plantations instead, and in addition, (b) Taiwan has successfully developed new export markets. Assumption (a) requires a supply-sided IO, while assumption (b) relates to changes in export, which requires a demand-driven IO. The final change in the output for this scenario will be the combined effects of the demand-driven and supply-sided changes. There will be two shocks for assumption (a): a reduction in the atemoya production and the additional production of sugar apple that will be sold to the domestic market. First, the reduction in atemoya production is based on 2020 data from the Ministry of Finance’s customs statistics on the atemoya export to China, which amounted to NTD 1255.71 million. Second, the additional production of sugar apples was computed as follows. In 2020, the total area of atemoya and sugar apple were 2815.19 hectares and 2529.10 hectares, respectively; and their total output value stood at NTD 2206.42 million and NTD 1857.18 million, respectively. Hence, their output value per hectare can be computed as NTD 0.784 million per hectare and NTD 0.734 million per hectare, respectively. Thus, the planting area that can change from atemoya to sugar apples is 1602.17 hectares (NTD 1255.71/0.784), which would lead to an increase in the output value of sugar apples by $1176.51 (1602.17*0.734). Therefore, the two shocks for the supply-sided IO will be a decrease of the output value of atemoya by NTD 1255.71 million and the increase the output value of sugar apples by NTD 1176.51 million. As for the demand-driven IO part, i.e., assumption (b), the shock will be similar to those in scenario 2.

5. Results and Discussion

5.1. Success in Using Controlled Atmosphere Technology

The main factors for the postharvest deterioration in atemoya are ripening and aging, chilling-induced browning, and the pathological breakdown.

Information about the application of CA or MA technology for atemoya is barely found in the literature to date. Wongs-Aree and Noichinda [6] recommend that the optimum gas conditions for atemoya storage are 3–5% oxygen plus 5–10% CO₂, with the temperature set at 13 °C. Under such conditions, the authors reckon that atemoya can last up to 4 weeks. Beaudry [21] reported that atemoya can tolerate as low as 1% oxygen. Yamashita et al. [22] used PD-955 film to pack cv. ‘PR3’ atemoyas at 15 °C for 17 days, which is a 30% increase in the postharvest life, compared to 13 days for the unpackaged control fruits. Therefore, Paull and Chen [23] suggested that CA or MA packaging has a potential application for the postharvest preservation of atemoya.

In this study, the integrated technology reduced the field pathogen infection by 20–30%, improving the precooling efficiency by 3–4 folds, and utilizing the CA transport technology that maintains a low oxygen and a high CO₂ environment in order to inhibit the ethylene biosynthesis, and thereby, suppress the ripening of atemoyas. We successfully prolonged the storage life of atemoya to 3–4 weeks.

The pilot shipments demonstrated that the fruits have been successfully shipped to Kuala Lumpur, Dubai, and Canada [24]. The cost-benefit analysis reveals that the shipping cost by using this technology is 10–25% lower than that of air transportation. Although slightly higher than reefer container transportation, the salability of atemoya transported using CA was over 90%, which was much higher than 20–70% of a normal reefer container, with a 7-day shelf life. Through the interdisciplinary collaboration and integration of the innovative techniques described earlier, the storage life of atemoya was successfully extended from 1–2 weeks to 3–4 weeks, which greatly enhances its capability to reach long-distance markets.

5.2. IO Analysis Results

The results of the IO analysis for the three scenarios in Section 4.2.2 are displayed on

Table 2. Economic impacts for Taitung under for three different scenarios.

Taitung’s Total Output Value in 2020 = NTD 105,280.17 Million
Scenarios	Impact (million NTD)	%-age change
Scenario 1: Atemoya completely disappears	–2232.96	–2.12%
Scenario 2: Exports to new markets	45.34	0.04%
Scenario 3: Exports to new market and shifts production to sugar apple	491.34	0.47%
Taitung’s total value-added in 2020 = NTD 60,429.50 million
Scenarios	Impact (million NTD)	%-age change
Scenario 1	–1663.24	–2.75%
Scenario 2	31.30	0.05%
Scenario 3	236.99	0.39%
Taitung’s total labor force in 2020 = 65,000 people
Scenarios	Impact	%-age change
Scenario 1	–2354 people	–3.62%
Scenario 2	50 people	0.08%
Scenario 3	2235 people	3.44%

Source: Authors’ computations.

. Scenario 1 shows the overall importance of atemoya to Taitung, that is, if the whole industry were to disappear, Taitung would lose NTD 2232 million or 2.12% of output value, NTD 1663 million or 2.75% of economic value-added, and 2354 or 3.62% of employed labor force. In Scenario 2, where Taiwan successfully exports to Malaysia, Canada, and Dubai, Taitung would gain about NTD 45 million in terms of output value, NTD 31.3 million in economic value-added, and add 50 employment opportunities. Lastly, for Scenario 3, where apart from the new export markets, Taiwan also shifts the production of previously exported atemoyas into sugar apples, the gains will be even larger: an additional output value of NTD 491 million, an additional value-added of NTD 237 million, and 2235 more employment.

6. Conclusions and Recommendation

The use of controlled atmosphere (CA) transport technology, integrated with reducing field pathogen infections and improving the precooling efficiency, successfully prolonged the storage life of atemoya up to 4 weeks; thereby, enabling successful shipments to Malaysia, the Middle East, and North America. The arrival salability was over 90% with 7 days of shelf life. Utilizing this technology is recommended if atemoya has to be transported for more than 10 days.

The IO analysis reveals that atemoya accounts for 2.12% of Taitung’s overall output value, 2.75% of its total value-added, and 3.62% of its total employment (Table 2), which shows how important this industry is to the economy of Taitung. Therefore, the sudden import bans imposed by its previous single export market dealt a heavy blow to the local rural economy. However, successfully exporting to new long-distance markets, enabled by the CA technology, contributed to the increased output value, value-added and employment by 0.04%, 0.05% and 0.08%, respectively. If in addition to this, the government were also to promote shifting to sugar apples, the additional output value, value-added and employment opportunity will be NTD 491 million, NTD 237 million and 2235 people, respectively; thus, shielding the rural economy from the impact of import bans.

Apart from changes in the atmospheric gas composition, another innovative solution to manage postharvest diseases in fresh fruits and vegetables is harnessing the biological properties of essential oil (such as from thyme, clove, and cinnamon) as alternatives to synthetic fungicides. Thyme oil vapor applied through fumigation has been found to be cost-effective for commercial farming [25]. Coupling them with MA technology has been proven to be a fruitful combination in prolonging shelf life [17]. Hence, future research can explore combining CA technology with essential oils to achieve similar outcomes.

This study presents a valuable case for using smart agriculture technology in successfully protecting a perishable fruit industry that has a thin domestic market from the market risk of relying on a single export market. It has also salvaged the rural economy that depends a great deal on the said industry.