1 Introduction

The Food and Agricultural Organization (FAO) (2011) reported that roughly one-third of the food that is produced for human consumption is lost or wasted globally, amounting to approximately 1.3 billion tons per year. The FAO also indicated that large amounts of resources used for the production of food that was wasted were consumed in vain, resulting in greenhouse gas (GHG) emissions during the production process that were produced for no additional benefit. The proportion of food loss and waste in the transportation stage for fruit and vegetables is approximately 10%, and this proportion is common among most countries and regions (FAO 2011).

The waste ratios for fruits and vegetables during transportation in 2017 in Japan were 17% and 10%, respectively (MAFF 2019). The ratios of these products are much higher than the ratios of other agricultural products (e.g., 1% for grains and 3% for tubers and roots) due to the susceptibility for fruit and vegetable injuries. To establish a countermeasure for reducing these ratios, many researchers have analyzed vibration characteristics during fruit and vegetable transport; additionally, the damage caused by vibration has been estimated, and optimal transportation methods have been suggested, including the packaging of some fruits (Takano et al. 2006; Kitazawa et al. 2010).

The packaging of fruits and vegetables serves some basic functions, such as protecting packed products; the corresponding roles are various and include protection from damage, deformation, putrefaction, and oxidation, the preservation of flavor and moisture, and the facilitation of handling by the retailer, during transportation and at home (Japan Packaging Institute 1996; Wikström et al. 2014). One of the core functions of packaging is protection from vibration during transportation. The vibration characteristics of strawberries during transportation (Nakamura et al. 2008) and strawberry damage due to vibration (Baba et al. 2012) were evaluated for certain kinds of packaging conditions. Highly functionalized packaging that prevents fruit and vegetable injury due to vibration during transportation may require surplus packaging, which is a concern. Surplus packaging causes increases in resource use and energy consumption during packaging production and waste processes. Conversely, transportation without packaging will cause an increase in food losses due to injury by vibration during transportation, and the additional production of products is required to compensate for the food losses. Therefore, less packaging for fruits and vegetables might also increase the environmental impacts attributed to increased food losses. Williams et al. (2008) and Molina-Besch et al. (2019) recommended that the balance between a decrease in the environmental burden due to decreasing food losses and an increase in the environmental burden related to surplus packaging should be quantified to assess the environmental impacts of food-packaging systems. Improving knowledge regarding ideal packaging considering both preventing fresh products from being injured during transportation and lowering energy inputs related to the production of optimal packaging is a key step in achieving rationalized food transportation during postharvest in a way that is sustainable from an environmental perspective. Therefore, the trade-offs between food loss and the environmental burden of packaging should be identified, especially for fragile fruits such as peaches (Nakamura et al. 2007), to lower the environmental transportation impacts associated with fragile fruits and vegetables.

There are many LCA studies of peach using several impact categories and functional units (FUs) (e.g., Ingrao et al. 2015 (FU, 1 ha of peach orchard); De Menna et al. 2015 (1 L of peach nectar); Vinyes et al. 2017 (production of 1 kg of peach); Pires Gaspar et al. 2018 (1 ha or 1 t of peach)). Additionally, there are LCA studies of food-packaging systems considering food loss. Conte et al. (2015) assessed the environmental impact caused by cheese production and argued that the ability of packaging to reduce food losses is an important factor that can decrease the environmental burden, beyond considering the burden of packaging production and disposal. However, there is no study of peach considering food loss. According to Corrado et al. (2017), moreover, few studies have assessed the impacts and benefits of food loss prevention and considered food loss during food transportation. Molina-Besch et al. (2019) concluded that the environmental impact of packaging production and the corresponding ability to reduce food loss have been insufficiently considered in LCA studies of food. Some authors have noted that many LCAs that include packaging neglect the influence of packaging on the environmental impact of the food supply chain (Silvenius et al. 2014; Pagani et al. 2015; review by Molina-Besch et al. 2019). Furthermore, many LCAs of packaging have focused on the packaging only and not on the packed product (Williams and Wikström 2010). Silvenius et al. (2014) evaluated the environmental impacts of soygurt, bread, and ham with packaging throughout their life cycles. They concluded that the effect of packaging contributed to only 1 to 5% of the impact of the entire product-packaging system of each commodity, except that for soygurt, for which the contribution of packaging was greater than 10% of the entire system. Additionally, Wikström et al. (2014) assessed the environmental impacts of the rice and yogurt life cycles and considered six packaging formats and three waste levels; they showed that the waste level of rice was more important than that of yogurt due to the higher global warming potential associated with the production of rice. These studies indicated that the effects of packaging and food loss (the waste level) on the environment differ for each product. Thus, assessing the relationship between the environmental impact of packaging and the corresponding ability to reduce food loss for each product is necessary to show a criterion which we continue to use packaging for protection of the product or decrease the use for reduce the environmental impact.

A review of packaging-related food losses and waste (Wohner et al. 2019) showed that in most cases, LCAs of food-packaging systems include no actual food losses or waste. Some LCAs have used an estimated ratio of food loss (Wikström et al. 2014) or a ratio based on the results of consumer surveys (Silvenius et al. 2014). This approach may lead to potentially misleading results regarding the relationship between food loss and the environmental impact of packaging. Moreover, few LCA studies have considered the relationship between food loss and the environmental impact in estimating the environmental burden of some fruits and vegetables throughout the entire life cycle (Sasaki et al. 2020); such products, especially fragile fruits (e.g., peaches and strawberries), often require packaging to prevent injury during transportation. This has not been assessed in the previous LCA studies of peach despite the fact that both excessive and inadequate packaging can increase the environmental burden of the peach life cycle. Therefore, we quantitatively evaluated positive and negative influences of packaging on the environmental burden thorough the life cycle of peach with actual food loss data to clear whether the positive effect of packaging can decrease the burden associated with the whole life cycle of peach or not; the positive aspect is to reduce the burden due to decreasing the food losses of peach during transportation, and the negative is to increase the burden due to package production and waste.

2 Materials and methods

2.1 Goal definition and functional unit

Food losses of fruits and vegetables during transportation are mainly due to damage by vibration and shock. The loss results in an environmental burden because it requires additional products to compensate for the loss and appropriate waste management measures. Reducing losses can potentially decrease the environmental burden associated with wasted products. However, improved packaging to protect products from injury and decreasing food losses (e.g., thickening the walls of packaging) may increase the environmental burden of the whole life cycle through the additional materials and energy required to produce the packaging. Hence, the goal of this study is to quantitatively determine the impact of packaging on the environmental burden in the peach life cycle, and the trade-offs between food loss and the environmental burden of packaging are discussed based on the obtained quantitative data.

When considering losses, 1 kg of undamaged peaches at the retail stage was defined as the functional unit. Hence, 1 kg or more of peaches was cultivated in the cultivation stage to compensate for the losses caused by vibration during transportation considering the ratio of loss (e.g., if the loss was 20%, 1.25 kg of peaches was cultivated; thus, 1 kg of undamaged peaches was transported to the retail location, and 0.25 kg of damaged peaches was wasted).

2.2 System boundary

The environmental impact of the life cycle was analyzed from farm to grave. Therefore, 10 stages, from cultivation to package waste (after consumption), were considered (Fig. 1). Consumer activities were excluded because peaches do not require cooking or preparation in the consumption stage, and therefore, consumer activities had an insignificant environmental impact on the peach life cycle; the LCA of the Mediterranean peach sector reported by Vinyes et al. (2017) showed that the environmental impact of the consumption stage was lower than that of other stages in the sector. We assumed that food loss only occurred during transportation from a fruit sorting facility to the wholesale market stage. Two scenarios, a packaging scenario and a nonpackaging scenario, were assessed to compare the environmental burden of each scenario and evaluate the differences.

Fig. 1
figure 1

System boundary. Some processes were excluded from the boundary; the reasons for these exclusions are explained in Sects. 2.5 and 2.6 in the manuscript

Full size image

2.3 Packaging conditions

The packaging conditions assessed in this study are shown in Fig. 2. The details of these conditions are as follows. (a) Each peach was covered with a ramified packaging material called foam net that is made of expanded polyethylene (EPE) (Kitazawa et al. 2008). The covered peaches were placed on cardboard during transportation. EPE cushion materials (an EPE net and an EPE sheet) were placed above and under the peaches covered with the foam nets, respectively. The masses of the foam net, EPE net, EPE sheet, and cardboard in the packaging scenario were 2.8 g, 11.7 g, 11.8 g, and 575.0 g per box, respectively; these masses were obtained by weighing the packaging materials of peaches used in a real-world transportation scenario in Japan. (b) The packaging in the nonpackaging scenario included only cardboard to compare the nonpackaging scenario with the packaging scenario based on the environmental impact of each approach. The same kind and amount (mass) of cardboard used in the packaging scenario were used in the nonpackaging scenario. The cardboard in the packaging and nonpackaging scenarios contained 15 peaches.

Fig. 2
figure 2

Overview of peach packaging (a packaging scenario; b nonpackaging scenario; c peach covered with a foam net)

Full size image

2.4 Vibration test and evaluation method of the damage area ratio

Vibration test methods were referenced from a previous report by Sasaki et al. (2020), and the details of the methods are as follows. Assuming that shock and vibration occur during peach transportation, a vibration test was conducted with a three-dimensional vibration testing machine (FVH146, Saginomiya Seisakusho Inc., Japan) that was located in the National Agriculture and Food Research Organization (NARO) laboratory in Japan. A random vibration test was conducted using the power spectrum density (PSD), which was established from actual transportation vibration data, because the Japanese Industrial Standards Committee (2018) recommends the random vibration test as the most suitable testing method; this test can reproduce the actual vibration that occurs during truck transportation to evaluate the vibration-induced characteristics of packaged freight. The vibration data were obtained from a previous report by Suda et al. (2016) to include actual data on the damage area ratio (food loss) in the analysis; they obtained data considering actual truck conditions at a speed of 80 km/h on an expressway in Japan. Thus, the transportation distance in this study was determined by multiplying the speed and the test time needed for each transportation distance (e.g., if the transportation distance was 500 km, peaches were vibrated for 6.25 h in the test). The peaches were repeatedly vibrated for 30 s, as noted in the data reported by Suda et al. (2016), because the data were almost no different during the measurements. The temperature in all the tests was set to 25 °C, and the humidity was not controlled, which was one of the assumed atmospheric conditions of peach transportation in Japan.

Damage evaluation was conducted in accordance with a publication by Mori et al. (2003). After the vibration test, the peaches were classified based on the degree of damage caused by two types of injury: scrapes and collapse on the peach surface. The two injuries were scored based on the damage degree of a tested peach (scrapes 1.0, 1.5, and 1.75; collapse 2, 3, 4, and 5). The collapse score was used when both injuries were present on the surface. The peaches were tested within 2 days after harvest. The damage area ratio of a peach was calculated by the following formula:

$$\mathrm{Damage\;area\;ratio }(\mathrm{\%})=\frac{\mathrm{scrape\;score\;or\;colloapse\;score}}{5}\times 100$$
(1)

The calculated ratios based on the transportation distance are shown in Table 1. The ratios in the packaging scenario increased with increasing transportation distance, but the ratios in the nonpackaging scenario did not increase for distances from 300 to 1000 km. Notably, the hardness of the tested peaches was not the same due to the nonuniformity of the samples in this study. Additionally, the vibration-damaged peaches in the cardboard served as a cushion for other peaches, thereby preventing vibration-related injury to the other peaches during the test.

Table 1 Damage area ratios of peaches for each transportation distance and packaging scenario
Full size table

2.5 Inventory analysis

The inventories for each packaging condition are described in Tables 2, 3, 4, 5, 6, and 7. The foreground data in Tables 2, 3, 4, 5, 6, and 7 are from the Plastic Waste Management Institute (2017). In the peach cultivation stage, the amount of peach production was calculated based on the damage area ratio with each transportation distance. The production and waste amounts of peaches and packaging were varied (or increased) with the transportation distance and damage area ratio because additional peaches and packages are required to compensate for the losses by vibration during transportation. The waste ratio of peaches after the consumption stage was referenced from the Standard Tables of Food Composition in Japan (MEXT 2015); the ratio was 15%, which also included inedible parts of a peach such as the peach seed. The waste and recycle ratios of plastic and cardboard are displayed in Table 8. The ratios of packaging and cardboard were referenced from the publication Basic Knowledge of Plastic Recycle 2018 (Plastic Waste Management Institute 2018) and Transition of Collect Rate on Cardboard (MOE 2016), respectively. The background data were referenced from IDEA ver.2.0 (Advanced LCA Research Group, Research Institute of Science for Safety and Sustainability, AIST; JEMAI, Japan), which includes raw material, energy consumption, transportation, and emission data regarding manufacturing and waste products; the database in IDEA ver. 2.0 can be accessed by users with an appropriate license (TCO2 Co., Ltd. 2018).

Table 2 Material and energy inputs per mass-based functional unit (kg of undamaged peaches) in the packaging and nonpackaging scenarios from cultivation to transportation from a fruit sorting facility to the wholesale market (transportation distance 0~300 km)
Full size table
Table 3 Material and energy inputs per mass-based functional unit (kg of undamaged peaches) in the packaging and nonpackaging scenarios from transportation from the wholesale market to retail to package waste (due to food loss) (transportation distance 0~300 km)
Full size table
Table 4 Material and energy inputs per mass-based functional unit (kg of undamaged peaches) in the packaging and nonpackaging scenarios from waste transportation to package waste (after consumption) (transportation distance 0~300 km)
Full size table
Table 5 Material and energy inputs per mass-based functional unit (kg of undamaged peaches) in the packaging and nonpackaging scenarios from cultivation to transportation from a fruit sorting facility to the wholesale market (transportation distance 500~2000 km)
Full size table
Table 6 Material and energy inputs per mass-based functional unit (kg of undamaged peaches) in the packaging and nonpackaging scenarios for transportation from the wholesale market to retail to package waste (for food loss) (transportation distance 500~2000 km)
Full size table
Table 7 Material and energy inputs per mass-based functional unit (kg of undamaged peaches) in the packaging and nonpackaging scenarios from waste transportation to package waste (after consumption) (transportation distance 500~2000 km)
Full size table
Table 8 Waste and recycle ratios of plastic and cardboard
Full size table

2.6 Data assumptions

Some assumptions were needed to create the inventory and precisely assess the environmental impact. The assumed data regarding each transportation distance and packaging condition were as follows. In all waste transportation stages, transport was conducted with a 2-t truck, and the distance was 50 km. Transportation from a fruit sorting facility to the wholesale market stage and from the wholesale market to the retail stage was accomplished with a 4-t truck. The transportation distances of the former transportation stage were set to 0 km, 100 km, 300 km, 500 km, 1000 km, and 2000 km (Table 1), and that of the latter transportation stage was set to 50 km, which was an assumed distance from Yamanashi, which is one of the main peach-producing districts in Japan, to Tokyo. The background data for peach cultivation in IDEA ver. 2.0 only included the environmental impact of transportation from farms to the wholesale market, not through a fruit sorting facility. This information was insufficient for completing the inventory required in this study because our system boundary included the environmental impact of transportation from farms to the wholesale market via a fruit sorting facility. To overcome this mismatch, we separated the impact from farms to the wholesale market via a fruit sorting facility to the impact from farm to a fruit sorting facility and from the facility to the wholesale market, and the details were as follows. (1) We regarded the impact of transportation from farms to the wholesale market in IDEA as the impact of transportation from farms to a fruit sorting facility; we had no choice to use the input data of peach cultivation in IDEA because the data could not be modified as an input data including the impact of transportation from farms to the wholesale market via a fruit sorting facility. (2) The impact of transportation from a fruit sorting facility to the wholesale market was considered separately from the impact of transportation from farms to the facility and added to the results of this study as a separate factor. We have confirmed that the impact in IEDA regarded as the impact of transportation from farms to a fruit sorting facility does not contribute to the burden for the peach cultivation stage and the whole life cycle (the following result is illustrated in Figs. 3 and 4).

Fig. 3
figure 3

Characterized results of the packaging scenarios for each transportation distance using a mass-based functional unit (kg of undamaged peaches). (1), (2), (3), (4), (5), and (6) show the results for distances of 0, 100, 300, 500, 1000, and 2000 km, respectively

Full size image
Fig. 4
figure 4

Characterized results of each peach cultivation process using a mass-based functional unit (kg of undamaged peaches). The total environmental impact of the processes included in the “Others” category in this figure contributed to less than 5% of the impact in the peach cultivation stage; these processes were categorized as follows: electricity, town gas 13A combustion, liquefied petroleum gas (LPG) combustion, tap water, kerosene combustion, fertilizer (content of potassium oxide), miscellaneous flexible plastic film, polyvinyl chloride film, sewerage treatment service, foamed plastic product (flexible and semirigid), industrial waste treatment, and Irrigation water

Full size image

The environmental impacts of manufacturing trucks, pallets, agricultural equipment, and some devices (e.g., fruit-sorting machines) were excluded because the effects of these products per FU are allocated based on the number of usable years (e.g., if the product is used for 15 years, the impact decreases by one fifteenth); this consideration was explained in a previous study (equations four to six) (Sasaki et al. 2019). Thus, the corresponding impacts of these products may be negligible. An LCA of peaches reported by Vinyes et al. (2017), which included machinery production emissions, showed that the environmental impact of these emissions was not dominant among the overall impact throughout the whole life cycle (the dominant processes were fertilizer and agrochemical production). The energy required for cooling during transportation was also excluded because cooling is not conducted in actual peach transportation in Japan (MAFF 2009). Only the impacts associated with incineration and landfills were included in the waste stage; the environmental impact of recycling was not included because this evaluation requires the consideration of other factors (e.g., a decrease in the environmental burden at the waste management stage) (Wada et al. 1996) beyond the scope of this study. All the wasted peaches were directly incinerated.

2.7 Impact assessment

The life cycle impact assessment method based on endpoint modeling (LIME2) (Itsubo and Inaba 2010) was used as the impact assessment method in this study because this approach has often been used to assess the environmental impacts of production activities in Japan (Komata et al. 2010; Hoshino et al. 2015). MiLCA ver.2.0. (JEMAI, Japan) is one of the most commonly used software programs in Japan for calculations supporting LCA and was used because it contains the inventory database (IDEA) and can implement LIME2 that is an impact assessment method specializing in actual conditions (e.g., environment and society) in Japan; the data in IDEA were obtained from statistical information, surveys, and studies published by the National Institute of Advanced Industrial Science and Technology (AIST) and the Japan Environmental Management Association for Industry (JEMAI) (TCO2 Co., Ltd. 2018; AIST 2014; JEMAI 2013). The calculated outputs are shown as characterized results and single score results. The indexes of characterization and weighting for the single score results were followed by LIME2. The characterized results are shown as the contribution (%) of each stage for each impact category. The unit of the single score result is expressed as the social cost on the basis of economic value (JPY) in LIME2. Social costs are the costs of health damage and/or environmental problems (e.g., the extermination of species) due to manufacturing a product (unit: Japanese yen, JPY) (Itsubo and Inaba 2010).

The impact categories investigated in this study were as follows: climate change (CC), photochemical oxidant (PO), resource consumption (RC), acidification (AC), waste (WA), ozone depletion (OZ), eutrophication (EU), ecotoxicity (ET), land use (LU), urban air pollution (UAP), indoor air pollution (IAP), human toxicity (HT), transportation noise (TN), energy consumption (EC), and water consumption (WC) (Table 9). The environmental impacts of IAP and TN were not observed, and thus, these impact categories were excluded from this study.

Table 9 Impact categories
Full size table

A hot spot analysis was conducted to identify the most relevant impact categories and processes based on the obtained single score results and to avoid detailed but discursive discussion of all 15 impact categories. The hot spot analysis was conducted in accordance with the Product Environmental Footprint Category Rules Guidance Version 6.3 (European Commission 2018); the most relevant impact categories were identified as all impact categories that cumulatively contribute to at least 80% of the total environmental impact based on the single score results (excluding the toxicity-related impact categories). The European Commission (2018) defines a hot spot as the most relevant life cycle stage that contributes at least 50% of the impact on any of the most relevant impact categories before normalization and weighting (based on the characterized results), excluding the toxicity-related impact categories. Thus, a hot spot in this study was determined based on the definition of the European Commission.

3 Results and discussion

3.1 Comparison of the environmental impacts between the packaging scenario and nonpackaging scenario

The reduction ratios of the characterized results in the packaging scenario to those in the nonpackaging scenario are shown in Table 10. Positive reduction ratios, indicating that the environmental burden in the packaging scenario was lower than that in the nonpackaging scenario, were demonstrated for all impact categories at distances from 100 to 2000 km. The highest ratio was 95.8% for the WA impact at a distance of 2000 km. These reduction ratios could have been affected by a difference in the amount of peach production per functional unit between the packaging scenario and the nonpackaging scenario (Table 1) because the main difference between the two scenarios was the amount of peach production (the damage area ratio); additionally, the difference in amounts was caused by a difference between each packaging condition. The results showed that the packaging, which protects the peaches from injury, has the potential to reduce the environmental burden of peach transportation. However, negative reduction ratios, indicating that the environmental burden in the packaging scenario is higher than that in the nonpackaging scenario, were shown for a distance of 0 km, and the UAP impact ratio was exceptionally low (− 6.9%). The reason for the negative ratios could be twofold. (1) The amount of peach production in the packaging scenario was the same as that in the nonpackaging scenario because no damaged product was produced at a distance of 0 km. (2) The package production stage in the packaging scenario had environmental impacts related to both package and cardboard production, but the production stage in the nonpackaging scenario included only the impact of cardboard production because the nonpackaging scenario did not include a package. For these reasons, the cultivation stage had the same impact in the packaging and nonpackaging scenarios, but the former scenario had a higher impact than the latter in the package production stage. Therefore, the negative ratios were confirmed. However, the reduction ratio immediately changed to a positive value when the loss of peaches occurred.

Table 10 Reduction ratios of the characterized results in the packaging scenario to those in the nonpackaging scenario for each impact category based on a mass-based functional unit (kg of undamaged peaches)
Full size table

3.2 Hot spot analysis for peach transportation and the characterized results of the packaging scenario

This study assessed the environmental impacts of the life cycle for 15 impact categories (Table 9), and only the most relevant impact categories determined by hot spot analysis are discussed in detail. The single score results of the packaging scenario are shown in Table 11. The LU and CC impacts were the most relevant impact categories for the single score results, and the total environmental impact of the two impact categories contributed to over 80% of the total single score value. Orikasa et al. (2015), however, reported that the interpretation of total environmental impacts is heavily dependent on the selected LU impact category (e.g., fallow paddy field, grass land, forest land, upland field, orchard, and cropland). This report clearly showed the uncertain impact of LU in life cycle evaluation. Therefore, we excluded the single score result for LU from this study.

Table 11 Single score results for the packaging scenario at each transportation distance in each impact category per mass-based functional unit (kg of undamaged peaches)
Full size table

Again, in Table 11, the CC, RC, and UAP impacts had large contributions to the single score results, and the total impact on the considered categories was over 80%. Hence, in accordance with the European Commission Standard (2018) considered in the hot spot analysis (i.e., considering the impact categories that contribute to the top 80% of the total singe score results), we focused only on three impact categories (CC, RC, and UAP) and excluded the impact of WA, although the WA impact is only 20–25% lower than that of RC and UAP.

The contributions of each life cycle stage to the CC, RC, and UAP impacts are shown in Table 12. Cultivation, package production, peach waste (due to food loss), and transportation from a fruit sorting facility to the wholesale market stage greatly contributed to the CC, RC, and UAP impacts, and the impacts of these stages were greater than 50% of the total influence in each impact category and for each transportation distance. Thus, the four stages were determined as hot spots in this study. The hot spots changed based on differences in the impact categories (e.g., the cultivation and package production stages were the hot spots at a distance of 1000 km for the UAP impact, but only the cultivation stage was a hot spot for the CC and RC impacts at the same distance) and transportation distances (e.g., the cultivation stage was a hot spot at a distance of 500 km for the UAP impact, but the cultivation and peach waste (due to food loss) stages were hot spots at a distance of 1000 km for the UAP impact). The results revealed that changes in the hot spots for the different impact categories and transportation distances should be considered to assess the environmental impacts of the peach life cycle.

Table 12 Contribution (%) of the characterized results in each life cycle stage of the packaging scenario for CC, RC and UAP using a mass-based functional unit (kg of undamaged peaches)
Full size table

The characterized results of the packaging scenario for each transportation distance are shown in Fig. 3. The hot spots in each process and for each transportation distance were discussed using the obtained characterized results, as follows.

3.2.1 Cultivation stage

The cultivation stage was the largest contributor in almost all impact categories, with contribution ratios to the CC, RC, and UAP impacts of 49.7 to 77.3%, 83.6 to 89.4%, and 36.4 to 68.6%, respectively. These results were similar to those of previous reports on the peach life cycle (Yoshikawa et al. 2007; Vinyes et al. 2017; Sasaki et al. 2020). Silvenius et al. (2014) assessed the environmental impacts of soygurt, bread, and ham through their life cycles, including household food waste and packaging stages; the results indicated that the production of food, which results in household food waste, was more significant than packaging production and waste. Similar results were observed in this study because the impact of the cultivation stage was dominant in the peach life cycle. From the results, reducing the environmental burden in the cultivation stage is the most effective way to reduce the burden throughout the whole life cycle of peaches. Moreover, the protection effect of packaging for fresh products to prevent injury during transportation can decrease the environmental burden in the cultivation stage. This reduction can occur because additional peaches are produced to compensate for damaged products due to vibration during transportation; additionally, the environmental burdens of these products are lowered because of the protection provided by packaging. Thus, positive reduction ratios in the characterized results are observed in the packaging scenario (Table 10).

The reduction ratios in Table 10 increased as the difference in the damage area ratio between the packaging scenario and the nonpackaging scenario increased with transportation distance (Table 1 and Table 10). This finding indicates that the effect of packaging (decreases in food loss and the environmental burden in the cultivation stage) is key for reducing the environmental burden throughout the whole life cycle of peaches; therefore, considering the trade-offs between food loss and the environmental burden in the peach life cycle, rational postharvest transport is sustainable from an environmental perspective.

The characterized results for these impact categories in the cultivation stage suggest that there was a clear hot spot in this stage, and the result is shown in Fig. 4. The characterized results indicate two notable findings: (1) Light oil combustion was the most relevant process for the CC impact and contributed to 28.0% of the total characterized result of the CC impact. Pesticide production, which was the second-most relevant process in the impact category, contributed to 13.2% of the total characterized result of the CC impact, and several other processes also contributed to approximately 10% of the total characterized result of the CC impact. The production of pesticides, disinfectants, and miscellaneous agricultural chemicals largely contributed to the UAP impact, accounting for 22.3%, 14.7%, and 13.7% of the total characterized result of the UAP impact, respectively. These results for the CC and UAP impacts show that multiple processes (light oil, gasoline and heavy fuel oil combustion, pesticides, disinfectants, miscellaneous agricultural chemicals and nitrogen fertilizer for the CC impact; light oil and heavy fuel oil combustion, pesticides, disinfectants, miscellaneous agricultural chemicals, and nitrogen fertilizer for the UAP impact) affected the environmental impact in the peach cultivation stage for the CC and UAP impacts. (2) Pesticide production was the most relevant process for the RC impact, contributing to 40.5% of the total characterized result. Disinfectant production and miscellaneous agricultural chemical production, which were the second- and third-most relevant processes for the impact category, contributed to 28.8% and 13.6% of the total characterized result for the RC impact, respectively. These results show that some specific processes (e.g., those involving pesticides, disinfectants and miscellaneous agricultural chemicals) exclusively affected the RC impact in the cultivation stage.

3.2.2 Package production stage

The package production stage had the second-largest contribution (Fig. 3) to the CC, RC, and UAP impacts at 13.6 to 20.5%, 9.9 to 10.4%, and 16.3 to 29.9%, respectively. Therefore, reducing the burden in this stage will contribute to a decrease in the total environmental burden in the peach life cycle. However, reducing the burden in this stage for the CC, RC, and UAP impacts can be achieved without increasing the damage area ratios of peaches. The characterized results of each package production process at distances from 500 km are shown in Fig. 5 to identify the most relevant process in this stage. Cardboard production was a large contributor to various impacts with values of 78.5% for the CC impact, 59.2% for the RC impact, and 78.8% for the UAP impact. Reducing the impacts of this process is an effective way to reduce the impact in the package production stage. The contribution of each process to this stage was almost the same at a distance from 0 to 2000 km.

Fig. 5
figure 5

Characterized results for each package production process using a mass-based functional unit (kg of undamaged peaches) (transportation distance 500 km). The contribution of each process to this stage was almost equal at a distance from 0 to 2000 km

Full size image

3.2.3 Peach waste (due to food loss) and transportation from a fruit sorting facility to the wholesale market stage

The contributions of peach waste (due to food loss) and transportation from a fruit sorting facility to the wholesale market stage increased for the CC and UAP impacts with increasing transportation distance. The contributions of the two stages at a distance of 2000 km were 14.1% and 21.0% for the CC impact and 25.9% and 20.6% for the UAP impact, respectively. The contribution in the peach waste (due to food loss) stage increased with increasing damage area ratio and was higher than the contribution of the package production stage to the UAP impact at a distance of 2000 km. Hence, decreasing the damage area ratio is necessary to reduce the burden in the peach waste (due to food loss) stage. One of the ways to reduce the burden is short-distance transportation with local production for local consumption because a shorter transportation distance results in a lower damage area ratio (Table 1). The ratio of transportation from a fruit sorting facility to the wholesale market stage for the CC and UAP impacts was approximately 20% at a distance of 2000 km; thus, reducing the environmental burden related to truck transportation is also needed in the scenario of long-distance transportation, e.g., changing the mode of transportation from trucks to trains or ships. According to Soode-Schimonsky et al. (2017), marine transportation is unsuitable for strawberry transportation because the method requires long periods of time, and the transported fruits deteriorate with the passage of time and prolonged respiration. Peaches also deteriorate via respiration during transportation, and the amount of damaged products (losses) can increase with respiration. Thus, such a transportation method can decrease the environmental burden in the transportation stage but increase the burden in the cultivation stage due to loss compensation. These perspectives should be considered in evaluating the environmental impacts of the long-term transportation of fresh products in the case of changing the transportation mode.

4 Conclusions

LCA was conducted for the peach life cycle to discuss the trade-offs between reducing food loss during transportation and increasing the energy consumption related to surplus packaging. This study assessed the environmental impacts of the life cycle for 15 impact categories and discussed 3 impact categories in detail based on the results of hot spot analysis. Compared with the environmental burden of the nonpackaging scenario, the burdens of the packaging scenario for all impact categories can be reduced; the CC, RC, and UAP impacts were reduced by up to 92.2%, 87.7%, and 94.1%, respectively. Peach packaging decreased the environmental burden because there were fewer injured peaches caused by vibration during transportation due to the protective effect of packaging. This result clearly showed that using packaging dramatically decreases the environmental burden of the peach life cycle, though it increases the burdens associated with package production and waste in the life cycle.

The CC, RC, and UAP impacts were the most relevant impact categories, contributing to over 80% of the total environmental impact based on the single score results. The cultivation stage made a large contribution (36.4 to 89.4%) to these impact categories. Other large contributors to the peach life cycle were the package production stage (9.9 to 29.9%), peach waste (due to food loss) stage (0.0 to 25.9%), and transportation from a fruit sorting facility to the wholesale market stage (0.0 to 20.6%). Many studies have focused on the cultivation stage (Vinyes et al. 2015; Nikkhah et al. 2017) and assessed the importance of reducing the environmental burden in this stage for sustainable agriculture. However, the abovementioned 3 stages also have high potential for generating high environmental burdens, especially in the package production stage, which was a large contributor at every transportation distance. Therefore, we should consider the environmental burden of the whole life cycle, and considering the trade-offs between food loss and environmental burden in the peach life cycle is imperative for decreasing the corresponding environmental impacts. Notably, packaging has high potential for decreasing the environmental burden of the peach life cycle, although it is also a large contributor to the environmental burden. In addition, the cultivation stage had the largest environmental impact on the peach life cycle. Thus, reducing the impact of this stage, especially by controlling pesticide, disinfectant, and light oil combustion processes, should be considered as a direct mitigation measure for reducing the overall environmental burden of the agricultural sector.

We claim through the results in this study that we should not conduct the excessive reduction of packaging for decreasing the environmental impact, which could rather increase the impact. Additionally, we should reconsider the positive and negative influence of packaging shown in this study such as decreasing the food losses and the loss-related environmental burden and increasing the burden for its production on environment to minimize the environmental burden through the life cycle of peach. Our future work will evaluate the environmental impacts of the peach life cycle using different kinds of packages to identify an optimal method for peach transport in terms of the trade-offs between food loss and environmental impacts. Moreover, we will evaluate the hot spots of various fruits and vegetables to explore the possibility for deploying sustainable postharvest technology.