植物工廠中調整光質與養液配方生產高附加價值芽菜與萵苣

Abstract

本研究首先探討如何透過人工光源光譜和養液配方的調控來提高完全人工光型植物工廠中萵苣與芽菜的附加價值，其次透過電力產能 (Energy Yield, EY)、光子產能 (Photon Yield, PY) 與益本比等三項量化指標來評估各作物與各處理間於栽培全程的效率與經濟效益。 芽菜的附加價值可透過提高其抗氧化力來達成；蘿蔔嬰、青花菜芽與紫甘藍芽以光量 50 μmol m–2 s–1，栽培 5 天，可有較高的抗氧化力。其中，全紅光 (R100) 能顯著提高三種芽菜的鮮重；全藍光(B100) 能顯著提高蘿蔔嬰與紫甘藍芽的花青素濃度。紅藍光 (R87:B13) 能顯著提高蘿蔔嬰維生素 C 濃度與 DPPH 清除率。有機發光二極體 (Organic Light-Emitting Diode, OLED，光質：R71:G18:B11:FR14) 可提高青花菜芽與紫甘藍芽的 DPPH 清除率、電力產能與光子產能，以OLED 栽培紫甘藍芽有最高的益本比。 紅橡萵苣的附加價值可透過改善其轉色與提高花青素含量且不影響產能來達成。由播種到採收共6 週，前 5 週使用 R80:B20 栽培，最末週換成 R20:B80 栽培 (SR5SB1)，與全程使用冷白 LED 之處理組相比電力產能雖降低了 1%，但花青素的電力產能提高了 159%、光子產能增加了 33%、花青素光子產能增加了 256%，益本比提高了 51%，此光配方可同時兼顧產量與花青素含量。 針對需要洗腎的重症腎臟病患的小眾市場可提供其適合於生食或熟食的三低 (低鉀、低鈉與低硝酸鹽濃度) 萵苣。選定每百克萵苣鮮重之鉀、鈉與硝酸鹽濃度上限分別為 80，30 與 250 mg，三項數值均低於上限值者以三低萵苣稱之。本研究開發出兩種栽培流程，分別可生產生食用與熟食用的三低萵苣，前者可降低鉀濃度約 90%，但鮮重只降低 23％；後者可降低鉀濃度約 52%，鮮重不降低。對於不喜歡使用化學養液偏愛有機產品的消費者而言，使用有機養液與益生菌栽培萵苣，也可提供其另一選擇。以本研究選定的有機養液栽培波士頓萵苣可顯著增加鮮重 134%，降低硝酸鹽濃度 60.4%。有機養液搭配光合菌能有效刺激根毛之發育，與山崎養液處理組相比三種萵苣 (波士頓、香波綠與皺葉) 地下部鮮重提高了 48%–143%。 本研究在使用PY 與EY的基礎上建立了益本比的概念，益本比較高代表相同的耗電支出所生產的產品的產值較高。三者共同可作為評估各栽培作物、各種光配方或各種栽培法等的效率與獲利之比較，譬如栽培芽菜比栽培波士頓萵苣的益本比高出 20%–630%，栽培低鉀萵苣比栽培波士頓萵苣的益本比提高約 30%。以SR5SB1 光配方栽培紅橡萵苣比使用冷白 LED的益本比高出 100%。

This study first explores how to increase the value-added of lettuce and sprouts in plant factory with artificial light (PFAL) through the regulation of artificial light recipe and nutrient solution recipe, followed by Energy Yield (EY), Photon Yield (PY) and Benefit-Cost ratio. Three quantitative indicators, are used to assess the efficiency and economic benefits of each crop and treatment during the whole cultivation process. The value-added of sprouts can be achieved by increasing its antioxidant capacity; radish, broccoli and red cabbage sprouts can be cultivated for 5 days with a light intensity of 50 μmol m–2 s–1, which can have a higher antioxidant capacity. Among them, full red light (R100) can significantly increase the fresh weight of three kinds of sprouts; full blue light (B100) can significantly increase the anthocyanin concentration of radish infants and purple cabbage sprouts. Red blue light (R87:B13) can significantly increase the vitamin C concentration and DPPH free radical scavenging rate of radish infants. Organic Light-Emitting Diode (OLED, light quality: R71:G18:B11:FR14) treatments increase DPPH free radical scavenging ability, EY and PY of broccoli sprouts and red cabbage sprouts. OLED treatments has the highest benefit-cost ratio of red cabbage sprouts. The value-added of red oak lettuce can be achieved by improving its color change and increasing anthocyanin content without reducing production capacity. From sowing to harvesting for 6 weeks, R80:B20 cultivation in the first 5 weeks, and R20:B80 cultivation (SR5SB1) in the last week, the EY was reduced by 1% compared with cold white LEDs in the whole process. However, anthocyanin-EY increased by 159%, PY increased by 33%, anthocyanin-PY increased by 256%, and the benefit-cost ratio increased by 51%. This light recipe can simultaneously take into account both yield and anthocyanin content. The niche market for severe kidney disease requiring dialysis can provide three low (low potassium, low sodium and low nitrate concentrations) lettuce suitable for ready-to-eat or ready-to-cook lettuce. The upper limit of the potassium, sodium and nitrate concentrations per 100 grams of fresh lettuce was 80, 30 and 250 mg, respectively, and the three values were lower than the upper limit. This study developed two cultivation processes, which can produce three low lettuces for ready-to-eat or ready-to-cook lettuce. The former can reduce the potassium concentration by about 90%, but the fresh weight is only reduced by 23%; the latter can reduce the potassium concentration by about 52%, and the fresh weight does not decrease. For consumers who don’t like to use chemical solution for production crops, the use of organic nutrients and benefit bacteria to cultivate lettuce can also provide another option. The cultivation of Boston lettuce with the organic nutrient significantly increased the fresh weight by 134% and reduced the nitrate concentration by 60.4%. The organic nutrient solution with photosynthetic bacteria can effectively stimulate the development of root hair. Compared with the Yamazaki nutrient treatment group, the fresh weight of the three kinds lettuce (Boston, Frill-ice and Frill lettuce) increased by 48%–143%. This study establishes the concept of benefit-cost ratio based on the PY and EY. The higher Benefit-Cost ratio, means higher the output value of the crops produced by the same power consumption. EY, PY and benefit-cost ratio can be used as a comparison between the efficiency and profitability of each cultivated crop, various light recipe or cultivation methods. From benefit-cost ratio, in PFAL planting sprouts is 20%–630% higher than boston lettuce, and cultivation of low-potassium lettuce can increase about 30% compared to boston lettuce. The SR5SB1 light recipe cultivated red oak lettuce increased the benefit-cost ratio by 100% compared to the control treatments (cool white LEDs).