Effect of mild heat treatment on browning-related parameters in fresh-cut Iceberg lettuce.
Vanden Abeele C, Raes K, Sampers I.
J Food Biochem. 2019 Jul;43(7):e12906. doi: 10.1111/jfbc.12906.

Fine monitoring of major phenolic compounds in lettuce and escarole leaves during storage.
Vidal V, Laurent S, Charles F, Sallanon H.
J Food Biochem. 2019 Feb;43(2):e12726. doi: 10.1111/jfbc.12726.

Pharmaceutical exposure changed antibiotic resistance genes and bacterial communities in soil-surface- and overhead-irrigated greenhouse lettuce.
Shen Y, Stedtfeld RD, Guo X, Bhalsod GD, Jeon S, Tiedje JM, Li H, Zhang W.
Environ Int. 2019 Jul 20;131:105031. doi: 10.1016/j.envint.2019.105031.

Lettuce-manufactured pharmaceuticals.
Lei L.
Nat Plants. 2019 Jul;5(7):646. doi: 10.1038/s41477-019-0484-y.

Lettuce (Lactuca sativa, variety Salanova) production in decoupled aquaponic systems: Same yield and similar quality as in conventional hydroponic systems but drastically reduced greenhouse gas emissions by saving inorganic fertilizer.
Monsees H, Suhl J, Paul M, Kloas W, Dannehl D, Würtz S.
PLoS One. 2019 Jun 20;14(6):e0218368. doi: 10.1371/journal.pone.0218368

Blue Light added with Red LEDs Enhance Growth Characteristics, Pigments Content, and Antioxidant Capacity in Lettuce, Spinach, Kale, Basil, and Sweet Pepper in a Controlled Environment.
Naznin MT, Lefsrud M, Gravel V, Azad MOK.
Plants (Basel). 2019 Apr 8;8(4). pii: E93. doi: 10.3390/plants8040093.

Reduced nitrogen supply enhances the cellular antioxidant potential of phenolic extracts through alteration of the phenolic composition in lettuce (Lactuca sativa L.).
Zhou W, Liang X, Zhang Y, Li K, Jin B, Lu L, Jin C, Lin X.
J Sci Food Agric. 2019 Aug 15;99(10):4761-4771. doi: 10.1002/jsfa.9721

Biofortification of Six Varieties of Lettuce (Lactuca sativa L.) With Iodine and Selenium in Combination With the Application of Salicylic Acid.
Smoleń S, Kowalska I, Kováčik P, Halka M, Sady W.
Front Plant Sci. 2019 Feb 19;10:143. doi: 10.3389/fpls.2019.00143.

Genetic and Phytochemical Characterization of Lettuce Flavonoid Biosynthesis Mutants.
Gurdon C, Poulev A, Armas I, Satorov S, Tsai M, Raskin I.
Sci Rep. 2019 Mar 1;9(1):3305. doi: 10.1038/s41598-019-39287-y.

Foliar Application of Vegetal-Derived Bioactive Compounds Stimulates the Growth of Beneficial Bacteria and Enhances Microbiome Biodiversity in Lettuce.
Luziatelli F, Ficca AG, Colla G, Baldassarre Švecová E, Ruzzi M.
Front Plant Sci. 2019 Feb 5;10:60. doi: 10.3389/fpls.2019.00060.

Safety

Arsenic accumulation in lettuce (Lactuca sativa L.) and broad bean (Vicia faba L.) crops and its potential risk for human consumption.
Yañez LM, Alfaro JA, Avila Carreras NME, Bovi Mitre G.
Heliyon. 2019 Jan 25;5(1):e01152. doi: 10.1016/j.heliyon.2019.e01152

Lettuce (Lactuca sativa L.) is an annual vegetable belonging to the Compositae family and is widespread in all countries with a temperate climate.

The genus "lactuca" has about 100 species.

Best known lettuce variety:

• Lactuca sativa L. var. crispa
• Lactuca sativa L. var. capitata
• Lactuca sativa L. var. Salanova
• Lactuca serriola
• Lactuca saligna
• Lactuca virosa
• Lactuca aculeata
• Lactuca altaica
• Lactuca azerbaijanica
• Lactuca dregeana
• Lactuca georgica
• Lactuca scarioloides
• Lactuca saligna
• Lactuca acanthifolia
• Lactuca aurea
• Lactuca longidentata
• Lactuca orientalis
• Lactuca quercina
• Lactuca sibirica
• Lactuca taraxacifolia
• Lactuca tatarica
• Lactuca viminea
• Lactuca watsoniana

Other varieties of lettuce with popular names:

• Lollo rossa
• Redin
• Iceberg

Lettuce may be green or red and it is, with chicory, among the best known salad in the world.

In the leaves are found phenolic compounds and ascorbic acid that give the lettuce antioxidant contents  especially in red lettuce. The minerals phosphorus, potassium, calcium and magnesium are present in larger quantities in green lettuce (1).

They are also present, especially in the leaves: saponins, alkaloids, sesquiterpenes and glucosinolates (2).

There are some carotenoid antioxidants in both varieties of lettuce (3):

• Neoxanthine and violaxanthine : 33%
  
• Lutein : 15% more
  
• Zeaxanthin : 0% for zeaxanthin
  
• Cryptoxanthin : 36%
  
• Lycopene : 0% sugar content
  
• Alpha carotene : 16%
  
• Beta beta carotene : 0%

Lettuce is therefore a plant with good characteristics for human health.
But the dangers are the soil pollution due to heavy metals and arsenic.

Lettuce studies

References_________________________________________

(1) Cultivar-Specific Performance and Qualitative Descriptors for Butterhead Salanova Lettuce Produced in Closed Soilless Cultivation as a Candidate Salad Crop for Human Life Support in Space.  El-Nakhel C, Giordano M, Pannico A, Carillo P, Fusco GM, De Pascale S, Rouphael Y.  Life (Basel). 2019 Jul 14;9(3). pii: E61. doi: 10.3390/life9030061.

(2) LC-MS Untargeted Metabolomics To Explain the Signal Metabolites Inducing Browning in Fresh-Cut Lettuce.  García CJ, García-Villalba R, Gil MI, Tomas-Barberan FA.  J Agric Food Chem. 2017 Jun 7;65(22):4526-4535. doi: 10.1021/acs.jafc.7b01667.

(3) Fruits and vegetables that are sources for lutein and zeaxanthin: the macular pigment in human eyes.  Olaf Sommerburg, Jan E E Keunen, Alan C Bird, Frederik J G M van Kuijk Br J Ophthalmol. 1998 Aug;82(8):907-10.