Effect of Different Elicitors and Preharvest Day Application on the Content of Phytochemicals and Antioxidant Activity of Butterhead Lettuce (Lactuca sativa var. capitata) Produced under Hydroponic Conditions

Abstract

The effect of four elicitors on phytochemical content in two varieties of lettuce was evaluated. The best preharvest day for application of each elicitor was chosen. Solutions of arachidonic acid (AA), salicylic acid (SA), methyl jasmonate (MJ), and Harpin protein (HP) were applied by foliar aspersion on lettuce leaves while cultivating under hydroponic conditions. Application of elicitors was done at 15, 7, 5, 3, or 1 day before harvest. Green lettuce showed the highest increase in phytochemical content when elicitors (AA, SA, and HP) were applied on day 7 before harvest. Similarly, antioxidant activity rose in all treatments on day 7. In red lettuce, the highest content of bioactive molecules occurred in samples treated on day 15. AA, SA, and HP were the elicitors with the highest effect on phytochemical content for both varieties, mainly on polyphenol content. Antioxidant activity also increased in response to elicitation. HPLC-MS showed an increase in the content of phenolic acids in green and red lettuce, especially after elicitation with SA, suggesting activation of the caffeic acid pathway due to elicitation.

Chemical characterization and functional properties of selected leafy vegetables for innovative mixed salads

“…These vegetables could therefore represent excellent sources of bioactive compounds with high impact on the nutrition and health of consumers. Similar behavior was found by Moreno‐Escamilla et al (), reporting a flavonoid content in red lettuce 1.62‐fold higher than in green lettuce. In the same way, Ninfali, Mea, Giorgini, Rocchi, and Bacchiocca () reported a flavonoid content in beet greens 1.36‐fold higher than in green lettuce and spinach.…”

Brosimum alicastrum Sw. (Ramón): An Alternative to Improve the Nutritional Properties and Functional Potential of the Wheat Flour Tortilla

“…On the other hand, it is the first time that vitamin C or total carotenoid content of RSF has been reported. Both values were lower than those reported in lettuce using the same analytical technique [13], so we considered RSF was not a good source of these compounds.…”

“…The content of carotenoids was determined following the method by Moreno-Escamilla et al [13] with some modifications. Flours and tortillas were dried at 45 • C in a vacuum oven (Shel Lab ® , Model VWR A-143, Tualatin, OR, USA) at 20 mm Hg for 36 h. Next, they were ground using a commercial blender (Nutribullet ® ) and kept at −18 • C in darkness for no more than 48 h. Subsequently, 0.3 g of dry ground sample were mixed with 10 mL of acetone (JT Baker ® , Fisher Scientific, West Palm Beach, FL, USA), sonicated (Branson ® , Model 5800, Fisher Scientific, West Palm Beach, Florida, USA) for 20 min and centrifuged (Eppendorf ® , Model 5810 R, Alto da lapa, Sâo Paulo, Brazil) at 3500 rpm for 10 min.…”

Seed Characteristics and Nutritional Composition of Pine Nut from Five Populations of P. cembroides from the States of Hidalgo and Chihuahua, Mexico

“…The total antioxidant activity was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and 2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging assays using the methodology according to Thaipong et al [34] and modified by Moreno-Escamilla et al [35]. For DPPH assay, the solutions were prepared in 80% methanol.…”