Cereal grains are the dietary staple in many countries, including the Republic of Korea. These grains are usually consumed cooked. Korean grown raw and cooked brown non-glutinous rice (BNR), white non-glutinous rice (WNR), oats, and barley were analyzed to assess the effects of cooking on dietary fiber and free sugar content. The largest decrease in total dietary fiber (TDF) after cooking was observed in barley (11.62±1.26 to 2.96± 0.90 g/100 g), and the smallest decrease was observed in oats (8.1±0.34 to 8.1±0.32 g/100 g). Soluble dietary fiber decreased in oats (3.35±0.94 to 1.25±0.03 g/100 g) while insoluble dietary fiber increased (4.76±0.78 to 6.90±0.30 g/100 g) after cooking. TDF content was not changed. Of the six free sugars routinely assessed, only sucrose was detected in BNR and WNR. Sucrose decreased by about 0.6 g/100 g in BNR, and was not detected in WNR, after cooking. Fructose, sucrose, and raffinose were detected in oats (0.08, 0.83, and 0.19 g/100 g) and barley (0.09, 0.58, and 0.22 g/100 g) Maltose was also detected in barley (0.09 g/100 g). Total sugar content decreased in every cereal grain sample after cooking. This research reveals that dietary fiber and free sugar content can be reduced by cooking cereal grains.

Kale (Brassica oleracea var. acephala) is one of the most frequently consumed leafy vegetables globally, as it contains numerous nutrients; essential amino acids, phenolics, vitamins, and minerals, and is particularly rich in glucosinolates. However, the differences in the biosynthesis of glucosinolates and related gene expression among kale cultivars has been poorly reported. In this study, we investigated glucosinolates profile and content in three different kale cultivars, including green (‘Man-Choo’ and ‘Mat-Jjang’) and red kale (‘Red-Curled’) cultivars grown in a vertical farm, using transcriptomic and metabolomic analyses. The growth and development of the green kale cultivars were higher than those of the red kale cultivar at 6 weeks after cultivation. High-performance liquid chromatography (HPLC) analysis revealed five glucosinolates in the ‘Man-Choo’ cultivar, and four glucosinolates in the ‘Mat-Jjang’ and ‘Red-Curled’ cultivars. Glucobrassicin was the most predominant glucosinolate followed by gluconastrutiin in all the cultivars. In contrast, other glucosinolates were highly dependent to the genotypes. The highest total glucosinolates was found in the ‘Red-Curled’ cultivar, which followed by ‘Man-Choo’ and ‘Mat-Jjang’. Based on transcriptome analysis, eight genes were involved in glucosinolate biosynthesis. The overall results suggest that the glucosinolate content and accumulation patterns differ according to the kale cultivar and differential expression of glucosinolate biosynthetic genes.

Antioxidants are food additives that extend the shelf life of food products by preventing lipid rancidity caused by active oxygen. They can either be naturally-derived or manufactured synthetically via chemical synthesis. In this study, method validation of five synthetic antioxidants, namely butylated hydroxyanisole, butylated hydroxytoluene, tertiary butylhydroquinone, propyl gallate, and disodium ethylenediaminetetraacetic acid, was performed using a high performance liquid chromatography–ultraviolet visible detector, and the method applicability was evaluated by analyzing foods containing antioxidants. The coefficient of determination (R2) average was 0.9997, while the limit of detection and limit of quantification were 0.02–0.53 and 0.07–1.61 mg/kg, respectively. The intra and inter-day accuracies and precisions were 83.2±0.7%–98.7±2.1% and 0.1%–5.7% RSD, respectively. Inter-laboratory validation for accuracy and precision was conducted using the Food Analysis Performance Assessment Scheme quality control material. The results satisfied the guidelines presented by the AOAC International. In addition, the expanded uncertainty was less than 16%, as recommended by CODEX. Consequently, to enhance public health safety, the results of this study can be used as basis data for evaluating the intake of synthetic antioxidants and assessing their risks in Korea.