Measurements that connect cultivation treatments to plant chemistry, volatile compounds, soluble solids, acidity, colour and texture.
| Outcome | Preferred method | interpretation |
|---|---|---|
| Volatile profile | HS-SPME GC–MS with internal standard and batch QC | chemical abundance is not identical to perceived aroma |
| Phenolics/target metabolites | validated HPLC/LC method | target list and extraction recovery reported |
| Mineral composition | ICP-OES/ICP-MS or validated equivalent | dry/fresh mass basis stated |
| Soluble solids | refractometry, °Brix | not universally equal to perceived sweetness |
| Titratable acidity | standardised titration | more informative than tissue pH alone for acid load |
| Colour | calibrated L*a*b* imaging or colorimetry | illumination and calibration controlled |
| Texture | instrumental compression/puncture plus sensory descriptor | method geometry and speed reported |
| Fresh/dry mass | traceable balance and drying method | concentration and total amount both reported |
Instrumental colour may be reported in CIE L*a*b* coordinates when acquisition, illuminant, observer, instrument geometry and calibration are fixed.
\nPlant position, leaf age, time of day, harvest-to-analysis delay, storage temperature and sample preparation are standardised. Lettuce research shows that nutrient solution, season and post-harvest handling can alter quality and shelf-life interpretation.
\nA treatment may increase a compound per gram while reducing total biomass. Report both concentration and total content per plant where feasible.
","text":"In brief Measurements that connect cultivation treatments to plant chemistry, volatile compounds, soluble solids, acidity, colour and texture. Measurement chain Outcome Preferred method interpretation Volatile profile HS-SPME GC–MS with internal standard and batch QC chemical abundance is not identical to perceived aroma Phenolics/target metabolites validated HPLC/LC method target list and extraction recovery reported Mineral composition ICP-OES/ICP-MS or validated equivalent dry/fresh mass basis stated Soluble solids refractometry, °Brix not universally equal to perceived sweetness Titratable acidity standardised titration more informative than tissue pH alone for acid load Colour calibrated L*a*b* imaging or colorimetry illumination and calibration controlled Texture instrumental compression/puncture plus sensory descriptor method geometry and speed reported Fresh/dry mass traceable balance and drying method concentration and total amount both reported Instrumental colour may be reported in CIE L*a*b* coordinates when acquisition, illuminant, observer, instrument geometry and calibration are fixed. [R45] Sampling control Plant position, leaf age, time of day, harvest-to-analysis delay, storage temperature and sample preparation are standardised. Lettuce research shows that nutrient solution, season and post-harvest handling can alter quality and shelf-life interpretation. [R26] Reporting concentration correctly A treatment may increase a compound per gram while reducing total biomass. Report both concentration and total content per plant where feasible.","source_ids":["R26","R45"],"visuals":[],"sources":[{"id":"R26","authors":"Luna, María C.; Martínez-Sánchez, Ascensión; Selma, María V.; Tudela, Juan A.; Baixauli, Carlos; Gil, María I.","year":2013,"title":"Influence of nutrient solutions in an open-field soilless system on the quality characteristics and shelf life of fresh-cut red and green lettuces (Lactuca sativa L.) in different seasons","publication":"Journal of the Science of Food and Agriculture","doi":"10.1002/jsfa.5777","source_type":"peer-reviewed research","relevance":"Supports controlling post-harvest handling and season when interpreting lettuce quality.","verification":"Publisher, PubMed, ISO or official proceedings metadata checked 2026-07-26","url":"https://doi.org/10.1002/jsfa.5777","verified_on":"2026-07-26","verification_status":"DOI METADATA CHECKED","verified_against":"Publisher, DOI landing page, PubMed or official repository where available"},{"id":"R45","authors":"International Organization for Standardization; International Commission on Illumination","year":2019,"title":"ISO/CIE 11664-4:2019 Colorimetry — Part 4: CIE 1976 L*a*b* colour space","publication":"International Standard","doi":null,"url":"https://www.iso.org/standard/74166.html","source_type":"official standard","relevance":"Defines calculation of CIE L*a*b* coordinates and colour differences for controlled instrumental colour reporting.","verification":"Official ISO current-edition record checked 2026-07-26","verified_on":"2026-07-26","verification_status":"OFFICIAL RECORD CHECKED","verified_against":"Official ISO catalogue record"}]}