**2.7. Total phenolic content**

**2.4. Chemicals**

The chemicals used for TPC, TAC, HPLC and ORAC are shown in **Table 1**.

acetate, hydrochloric acid, sodium carbonate, 2,4,6-Tri(2-pyridyl)-1,3,5 triazine and the Folin-Ciocalteu reagent

m-Coumaric acid, o-Coumaric acid, kaempferol-3-glucoside, quercetin-3 glucoside, cyanidin-3-glucoside and

dihydrochloride (AAPH), fluorescein disodium and 6-hydroxy-2,5,7,8 tetramethylchroman-2-carboxylic acid

pelargonidin-3-glucoside

Ellagic acid and pelargonidin-3-rutinoside

**Procedure Chemicals Company**

TPC and TAC Gallic acid, ferric chloride, sodium

200 Phenolic Compounds - Natural Sources, Importance and Applications

HPLC gallic acid, p-Coumaric acid,

**2.5. Soluble solids content, titratable acidity and firmness**

**Table 1.** The chemicals used for TPC, TAC, HPLC and ORAC.

ORAC 2,2-Azobis(2-methylpropionamidine)

(Trolox)

Weight loss = weight day *<sup>x</sup>* − weight day *x*+<sup>1</sup>

weightday *x*+1 is the total weight of the same five berries day after.

mould were ranked from 1 ('no disease') to 5 ('the presence of mould') [24].

**2.6. Fruit postharvest quality**

where weightday *<sup>x</sup>*

Five strawberries were selected randomly and blended thoroughly using a Supreme Juicerator (Acme Juicer Manufacturing Co., New Hartford, CT, USA), and the SSC of the juice was measured at room temperature with a refractometer (Abbe Mark II, Reichert-Jung, Depew, NY, USA) as described previously [25]. TA was measured by diluting 1 mL of strawberry juice with 9 mL of distilled water, adjusted to pH 8.1 using 0.1 N of NaOH (Accumet AB15 Basic pH metre; Fisher Scientific) as described previously [25]. Firmness was ranked from 1 (very soft) to 5 (very firm).

Five fruits per replicate randomly selected from each plot were placed on Whatman no. 1 filter paper in open Petri dishes and left at room temperature (23°C) to evaluate postharvest deterioration. Fruit weight loss and juice leakage, fruit glossiness and the postharvest incidence of grey mould (*Botrytis cinerea* Pers.) were monitored daily until the fruits were considered non marketable. Fruit weight loss was calculated according to Wang et al. [26] using the following method:

The fruit juice leakage was ranked from 1 ('no leak or juice loss') to 4 ('significant fruit leak or juice loss'), fruit glossiness was ranked from 1 ('dull') to 3 ('shiny'), and presences of grey

is the total weight of the five tested berries in each Petri dish and

. (1)

Sigma Chemical Co. (St. Louis, MO,

Sigma Chemical Co. (Oakville, ON,

Apin Chemicals (Abingdon, UK)

Sigma Chemical Co. (Oakville, ON,

USA)

Canada)

Canada)

The TPC was measured in accordance with the slightly modified Folin-Ciocalteu (FC) method [27]. In a 10-mL vial, a standard or sample extract (0.02 mL) and 0.1 mL of FC reagent were mixed with 1.58 mL of water for 3 min. After that, 0.3 mL of Na<sup>2</sup> CO<sup>3</sup> (7.5%) was added, and the solution was allowed to stand for 30 min at 40°C. Absorption was measured at 765 nm with an Ultrospec 3100 pro UV/visible spectrophotometer (Fisher Scientific, Ottawa, ON, Canada). The result was expressed as gallic acid equivalent (GAE) in mg/g of fresh frozen weight using gallic acid as standard. The sample concentrations beyond 500 μg mL−1 were diluted before final analysis to suit the linear range of the standard curve.
