Food Science and Nutrition

The peel of Gac fruit (Momordica cochinchinensis Spreng.) contains high levels of bioactive compounds, especially carotenoids which possess significant antioxidant capacities. However, the peel of Gac is regarded as a waste from the production of carotenoid‐rich oil from Gac fruit. In this study, carotenoids of Gac peel were extracted by microwave‐assisted extraction (MAE) and ultrasound‐assisted extraction (UAE) using ethyl acetate as extraction solvent. The effect of extraction time and different levels of microwave and ultrasonic powers on the yield of total carotenoid and antioxidant capacity of the extracts were investigated. The results showed that an extraction at 120 W for 25 min and an extraction at 200 W for 80 min were the most effective for MAE and UAE of the Gac peel samples, respectively. The maximum carotenoid and antioxidant capacity yields of UAE were significantly higher than those of the MAE. The antioxidant capacity of extract obtained by the UAE was also significantly higher that of the conventional extraction using the same ratio of solvent to material. The results showed that both MAE and UAE could be used to reduce the extraction time significantly in comparison with conventional extraction of Gac peel while still obtained good extraction efficiencies. Thus, MAE and UAE are recommended for the improvement of carotenoid and antioxidant capacity extraction from Gac peel.

The aril around the seeds of Gac fruit is rich in fatty acids and carotenoids (lycopene and β‐carotene). Understanding how these qualities are affected by fruit maturity at harvest may identify indices for quality assessment. Some physical and chemical properties of Gac fruit were determined for fruit harvested between 8 and 16 weeks after pollination (WAP). Fruit respiration rates and ethylene production rates were assessed after harvest and up to 20 days in storage at 20°C. Fruit harvested at 14 WAP had the highest oil (0.27 ± 0.02 g/g DW), lycopene content (0.45 ± 0.09 mg/g FW), and β‐carotene content (0.33 ± 0.05 mg/g FW) which declined by 16 WAP. External skin color and aril TSS were indicative of oil and carotenoid contents in aril. Skin color, TSS and potentially firmness were good indices of fruit quality. Harvesting less mature fruit at 12 WAP would be practical as the fruit were firmer and more capable of transport; however, quality during postharvest ripening may be limited. Fruits continued to ripen after they were harvested and an ethylene peak in the least mature fruit may reflect a climacteric behavior but this needs further investigation.

The peel of Gac fruit (Momordica cochinchinensis Spreng.) contains high levels of bioactive compounds, especially carotenoids which possess significant antioxidant capacities. However, the peel of Gac is regarded as a waste from the production of carotenoid‐rich oil from Gac fruit. In this study, carotenoids of Gac peel were extracted by microwave‐assisted extraction (MAE) and ultrasound‐assisted extraction (UAE) using ethyl acetate as extraction solvent. The effect of extraction time and different levels of microwave and ultrasonic powers on the yield of total carotenoid and antioxidant capacity of the extracts were investigated. The results showed that an extraction at 120 W for 25 min and an extraction at 200 W for 80 min were the most effective for MAE and UAE of the Gac peel samples, respectively. The maximum carotenoid and antioxidant capacity yields of UAE were significantly higher than those of the MAE. The antioxidant capacity of extract obtained by the UAE was also significantly higher that of the conventional extraction using the same ratio of solvent to material. The results showed that both MAE and UAE could be used to reduce the extraction time significantly in comparison with conventional extraction of Gac peel while still obtained good extraction efficiencies. Thus, MAE and UAE are recommended for the improvement of carotenoid and antioxidant capacity extraction from Gac peel.

Các nghiên cứu dịch tễ học cho thấy rằng tỷ lệ mắc các bệnh mãn tính nhất định thấp ở những vùng tiêu thụ gạo trên thế giới có thể liên quan đến hàm lượng hợp chất chống oxi hóa có trong gạo. Các phân tử có hoạt tính chống oxi hóa có trong gạo bao gồm axit phenolic, flavonoid, anthocyanin, proanthocyanidin, tocopherol, tocotrienol, γ-oryzanol và axit phytic. Bài tổng quan này cung cấp thông tin về hàm lượng của những hợp chất này trong gạo thông qua một cơ sở dữ liệu về thành phần thực phẩm được xây dựng từ việc tổng hợp dữ liệu từ 316 bài báo. Cơ sở dữ liệu này cung cấp quyền truy cập vào thông tin mà nếu không sẽ vẫn ẩn giấu trong tài liệu. Ví dụ, trong số bốn loại gạo được phân loại theo màu sắc, các giống gạo đen nổi lên là những giống có hoạt tính chống oxi hóa cao nhất, tiếp theo là các giống gạo tím, đỏ và nâu. Hơn nữa, các hợp chất không hòa tan có vẻ như tạo thành phần chính của axit phenolic và proanthocyanidin trong gạo, nhưng không phải của flavonoid và anthocyanin. Rõ ràng, để tối đa hóa việc tiếp nhận các hợp chất chống oxi hóa, gạo nên được tiêu thụ chủ yếu dưới dạng cám hoặc nguyên hạt. Về vấn đề giống, các giống gạo japonica được tìm thấy có nhiều hợp chất chống oxi hóa hơn so với các giống gạo indica. Tổng thể, các phần hạt gạo có vẻ là nguồn giàu hợp chất chống oxi hóa. Tuy nhiên, trên cơ sở hạt nguyên và ngoại trừ γ-oryzanol và anthocyanin, hàm lượng chất chống oxi hóa trong các loại ngũ cốc khác có vẻ cao hơn so với trong gạo.

Poor water solubility, emulsifying, and foaming properties of gluten protein have limited its applications. Gluten is structured by covalent (disulfide bonds) and noncovalent bonds (hydrogen bonds, ionic bonds, hydrophobic bonds) which prone to alteration by various treatments. Enzyme modification has the ability to alter certain properties of gluten and compensate the deficiencies in gluten network. By hydrolyzing mechanisms and softening effects, hydrolytic enzymes affect gluten directly and indirectly and improve dough quality. The present review investigates the effects of some hydrolytic enzymes (protease and peptidase, alcalase, xylanase, pentosanase, and cellulase) on the rheological, functional, conformational, and nutritional features of gluten and dough. Overall, protease, peptidase, and alcalase directly affect peptide bonds in gluten. In contrast, arabinoxylan, pentosan, and cellulose are affected, respectively, by xylanase, pentosanase, and cellulase which indirectly affect gluten proteins. The changes in gluten structure by enzyme treatment allow gluten for being used in variety of purposes in the food and nonfood industry.

An immobilized enzyme system for bioconversion of Lo Han Kuo (LHK) mogrosides was established. β‐Glucosidase which was covalently immobilized onto the glass spheres exhibited a significant bioconversion efficiency from pNPG to pnitrophenol over other carriers. Optimum operational pH and temperature were determined to be pH 4 and 30°C. Results of storage stability test demonstrated that the glass sphere enzyme immobilization system was capable of sustaining more than 80% residual activity until 50 days, and operation reusability was confirmed for at least 10 cycles. The Michaelis constant (K_m) of the system was determined to be 0.33 mM. The kinetic parameters, rate constant (K) at which Mogrosides conversion was determined, the τ₅₀ in which 50% of mogroside V deglycosylation/mogroside IIIE production was reached, and the τ complete of complete mogroside V deglycosylation/mogroside IIIE production, were 0.044/0.017 min⁻¹, 15.6/41.1 min, and 60/120 min, respectively. Formation of the intermediates contributed to the kinetic differences between mogroside V deglycosylation and mogroside IIIE formation.

Hainan/Eksotika papaya is a popular cultivated plant in Hainan Island, China. Papaya seed oil (PSO) contains functional compounds with good antioxidant activity, especially monounsaturated fatty acids. In this work, the ultrasound‐assisted extraction (UAE) of PSO was optimized using response surface methodology. It was found that the optimal extraction performance was realized when the elevated time was set to 20 min, the ultrasound power was set to 250 W, and the n‐hexane‐to‐sample ratio was set to 16:1 (v/w). The highest yield of PSO (32.27%) was obtained under the optimal conditions, and PSO showed good oxidative stability. Differential scanning calorimetry analysis showed that the melting point of Hainan/Eksotika PSO was low, while its crystallization temperature was high. FTIR and NMR were used to analyze the chemical structure of PSO, which also proved that PSO possessed good stability without oxidative degradation. In addition, scanning electron micrograph was employed to investigate the change in seed microscopic structure. The results showed UAE caused serious structural damage of sample cell membranes and walls, which help oil access to the solvent with a high extraction ratio. The results indicated that UAE is an efficient environmental‐friendly, and promising technique could be applied to produce PSO or other edible oil with a better health‐beneficial value in food industry.

Grass turtle muscle was hydrolyzed with papain enzyme to produce protein hydrolysate (PH) and the degree of hydrolysis (DH) was determined. Under optimal conditions, the highest DH was 19.52% and the yield was recorded as 17.26%. Protein content of the hydrolysates was ranged from 73.35% to 76.63%. Total amino acids were more than 96.77% for each PH. The PH obtained at DH 19.52% achieved excellent solubility and emulsifying activity which were 95.56% and 108.76 m²/g, respectively at pH 6. Foam capacity amounted 100% in PH of DH 19.52% at pH 2, and water‐holding capacity was 4.38 g/g. The antioxidant activity showed the strongest hydroxyl radical scavenging activity (95.25%), ABTS (84.88%), DPPH (75.89%), iron chelating (63.25%), and cupper chelating (66.90%) at DH 11.96%, whereas reducing power (0.88) at DH 19.52%. Thus, the findings indicated that utilization of grass turtle muscle protein hydrolysate is a potential alternative protein resource to improve the nutritional and functional properties in food ingredients and product formulations.

The objective of this study was to determine important chemical characteristics of a full‐strength liquid smoke, Code 10‐Poly, and three refined liquid smoke products (AM‐3, AM‐10 and 1291) commercially available (Kerry Ingredients and Flavors, Monterey, TN). The pH of the products were significantly different (P < 0.05) and ranged from 2.3 (Code 10‐Poly) to 5.7 (1291). The pH was inversely correlated with titratable acidity (R² = 0.87), which was significantly different (P < 0.05) among products ranging from 10.3% acetic acid (Code 10‐Poly) to 0.7% acetic acid (1291). Total phenol content was quantified using the Gibbs reaction; the only liquid smoke containing appreciable level of phenolic compounds was Code 10‐Poly at 3.22 mg mL⁻¹. Gas chromatography‐mass spectrometry (GC‐MS) analysis of liquid smoke dichloromethane extracts revealed that carbonyl‐containing compounds were major constituents of all products, in which 1‐hydroxy‐2‐butanone, 2(5H)‐furanone, propanal and cyclopentenone predominated. Organic acids were detected by GC‐MS in all extracts and correlated positively (R² = 0.98) with titratable acidity. The GC‐MS data showed that phenolic compounds constituted a major portion of Code 10‐Poly, and were detected only in trace quantities in 1291. The refined liquid smokes had lighter color, lower acidity, and reduced level of carbonyl‐containing compounds and organic acids. Our study revealed major differences in pH, titratable acidity, total phenol content, color and chemical make‐up of the full‐strength and refined liquid smokes. The three refined liquid smoke products studied have less flavor and color active compounds, when compared with the full‐strength product. Furthermore, the three refined products studied have unique chemical characteristics and will impart specific sensorial properties to food systems. Understanding the chemical composition of liquid smokes, be these refined or full‐strength products, is an important step to establish their functions and appropriate use in food systems.

The different species of Arum maculatum plant can be found in all over the world, and a wide range of medicinal applications has been mentioned for them. Thus, it can also be valued as a source of natural compounds with antioxidant and antimicrobial activities. In this study, the effect of solvents (water, ethanol, ethanol:water (50:50)) and extraction methods (maceration and ultrasound) on the extraction yields and bioactive properties of extracts were analyzed. The antioxidant capacity of Arum maculatum leaves extracts was investigated, and the concentrations of total phenolics, tocopherols, tannins and flavonoids were determined. 1,1‐diphenyl 2‐picrylhydrazyl free radical (DPPH), β‐Carotene bleaching, and oxidative stability index (OSI) were used to determine antioxidant activity. The ability to scavenge radicals was measured in these experiments by the discoloration of the solution. Also, the antimicrobial activity of different extracts against Gram‐positive (Staphylococcus aureus and Listeria monocytogenes) and Gram‐negative bacteria (Escherichia coli, Salmonella enteritidis, and Pseudomonas aeruginosa) was evaluated by using of microdilution and agar diffusion assays. The results demonstrated that ultrasonic extracts (especially ethanol:water (50:50) solvent) had the higher extraction yield and antioxidant potential than maceration extracts. All extracts were effective against all tested bacteria, and Listeria monocytogenes was the most sensitive bacterium with lowest MIC value (12.5 mg/ml) and biggest diameter of growth inhibition zone (13.77 mm). Generally, this Arum maculatum leaves extracts can be suggested as an economical source of antioxidant and antimicrobial agents and can be a suitable substitute for artificial and chemical food preservatives.