Enhancing the enzymatic browning inhibition capacity of Moringa oleifera seed extract via the Maillard reaction

The antioxidant and anti-browning activity of heated plant extracts have been attributed to the formation of Maillard reaction products (MRPs) via the Maillard reaction (MR). The inhibitory effect of heated Moringa oleifera (MO) seed extract on banana polyphenol oxidase (PPO) was investigated. The Plain MO seed extracts and those with added glucose and glycine (1.5 mM each) were heated at 100°C for 15, 30, 60 and 120 min. The pH and brown colour development decreased and increased significantly (P <0.05) with increased reaction time, respectively, with heated moringa glucose-glycine HMGGL for 120 min exhibiting the highest pH reduction (2.58) and darkest extracts at an L* value of 8.11. This phenomenon is associated with progression of the MR. With reference to enzymatic browning, heated MO seed extracts exhibited stronger inhibitory effect against banana PPO activity in vivo and in vitro than the unheated counterpart. Evident to this are the higher inhibition percentages and lower ΔE values. Among model systems, the highest in vitro browning inhibition was exhibited mostly by longer heating times of 60 and 120 min. Model system HMGGL 120 min proved to be superior at 96% inhibition, which was comparable to known synthetic commercial antioxidants such as ascorbic acid (AA) at 99%, as well as ethylenediaminetetraacetic acid (EDTA) and citric acid (CA), both at 100% inhibition. In vivo enzymatic browning inhibition followed a similar trend, where the brown pigment (melanin) intensified as shown by an increase in ΔE as the storage time increased from 0.5 to 24 h. The model system UMGGL exhibited highest inhibition of brown melanin (p <0.05). Although it was the best amongst other model systems, it was surpassed by synthetic antioxidants AA, EDTA and CA, which were ranked amongst the top three in inhibiting brown pigment formation in vivo. To further illustrate the effect of MR augmented MO seed extracts on enzyme activity inhibition, UMGGL 60 and 120 at 5 and 24 h storage surpassed the inhibitory effect of AA. At the said storage times, AA lost its inhibitory potential against pigment formation. This was due to oxidation of AA to form dehydroascorbic acid, which lacks inhibitory potential. This study proved that heating MO plant extracts increases their enzymatic browning inhibition potential, furthermore, the inhibitory capacity was heightened when reacted via the MR

Antioxidant activity of sugar-amino Maillard reaction products (MRPs) as a function of reactant type, temperature, time and molecular weight fraction

Antioxidant activity of sugar-amino Maillard reaction products (MRPs) as a function of reactant type, temperature, time and molecular weight fraction 16th World Congress of Food Science and Technology, Foz do Iguaçu, Brazil, 5-9 August 201

Antioxidant effect of Maillard reaction products in a lipid-rich model system

Antioxidant effect of Maillard reaction products in a lipid-rich model system 11th Maillard Reaction Symposium, Nancy, France, 16-20 September 201

Effects of high-intensity ultrasound and oil type on the Maillard reaction of d-glucose and glycine in oil-in-water systems

Food processing: ultrasound betters flavour off sugar and amino acid Ultrasound generates more flavour species in oil-in-water mixtures containing sugar and amino acid than heating, but meanwhile degrades oils. Weibiao Zhou at National University of Singapore and collaborators in China studied the effect of high-intensity ultrasonic processing on model food systems with sugar and amino acid in mixtures of water and different oils. The researchers found that high-intensity ultrasound can speed up the Maillard reaction, a chemical reaction that yields various flavour compounds from amino acids and reducing sugars, because it can induce a temporary condition of high temperature and high pressure and promote the mixing between water and oil. On the other hand, ultrasound is responsible for increased oxidation of unsaturated oils, leading to off-flavours and loss of nutrients. These results may help improve ultrasound-assisted food processing techniques

Effect of Rocha pear peel extracts added to wheat and rye bread formulations on acrylamide reduction and sensory quality maintenance

Conference paper inclued in the book that contains the proceedings of the INternational CongRess on Engineering and Sustainability in the XXI cEntury – INCREaSE 2019, which was held in Faro, Portugal, from October 09 to 11, 2019.Pear peels are seen as potentially valuable for their low-cost beneficial components content such as polyphenols. These may reveal acrylamide (AA) mitigation effect and thus their application in a susceptible food matrix, such as bread, should be considered. Aiming to assess the AA reduction potential of Rocha pear peels in bread and the effects on its sensory quality, two types of bread highly consumed in Portugal - wheat (WB) and rye (RB) – were assayed with the extract of these by-products, in two forms aqueous [a] and dry [d]. Eight bread batches were produced (4 WB; 4 RB); each composed of one control sample and five replicates added with extract. The process included controlled fermentation, and cooking in a traditional oven (TO) and convection oven (CO). Hedonic evaluation was made to samples of each batch. Overall, slight differences were observed for WB and RB hedonic evaluation between the control sample and those with both extract forms. Lower scores were observed in both bread types baked in CO, with [d] comparing with the control; for bread with [a], oven influence varied; higher scores for WB in CO and for RB baked in TO, comparing with the control. Regarding AA reduction, the highest mitigation rate was accomplished by the [d] in WB cooked in a CO, 27.3%. However, for RB the best formulation was obtained with [d] in the TO, 19.2%. These results support the importance of selecting the best baking process according to the varieties of bread and AA reduction.The authors appreciate the financial support of MISAGE project LISBOA-01-0145-FEDER-024172). This project has received financial support from the Fundação para a Ciência e a Tecnologia (FCT), Portugal.info:eu-repo/semantics/publishedVersio

Chemical compositions, total phenolic contents, antimicrobial and antioxidant activities of the extract and essential oil ofThymbra spicataL. growing wild in Turkey

YUCEL, Ersin/0000-0001-8274-7578WOS: 000568468700003In the study, chemical composition, total phenolic contents, antioxidant capacity and antimicrobial activities of the extract and essential oil ofThymbra spicataL. growing wild in Turkey were investigated. Chemical compositions ofT. spicataL. extract and essential oil were determined using the GC-MS method. the main components of the plant extract were carvacrol (88.75%) and acetic acid (11.25%) while the main components of the plant essential oil were carvacrol (56.03%),transcaryophyllene (10.41%),p-cymene (9.61%) and gamma-terpinene (6.87%). the total phenolic contents of extract and essential oil were 1350 and 3440 mu g GAE g(-1), respectively. Antioxidant activities of the samples were tested using DPPH and ABTS(+)radical scavenging activities. the antioxidant capacity of the extract and essential oil (50.51-98.28%) is highly correlated with their phenolic contents. the antimicrobial effects of this plant were tested by disc diffusion and broth dilution methods against seven bacteria. the highest inhibition zone values were observed againstStaphylococcus aureusas 15 +/- 7 mm and 50 +/- 10 mm, for extract and essential oil ofT. spicataL., respectively. According to broth dilution method,Bacillus subtilisandListeria monocytogeneswere found to be the most resistant bacteria to theT. spicataL. essential oil (0.625%). the oil sample showed high bactericidal effect against all test microorganisms (0.313-1.25%). Essential oil of the plant exhibited higher antimicrobial activity than the extract. As a result,T. spicataL. could be used in pharmaceutical and food industries as a natural antioxidant and in antimicrobial products