A brief hot-water treatment alleviates chilling injury symptoms in fresh tomatoes.

BACKGROUND: Reducing the negative effects of chilling injury (CI) in tomatoes after harvest is essential to ensure good quality and to minimize losses. CI is a postharvest disorder associated with the generation of reactive oxygen species (ROS) in the fruit. Therefore, antioxidant accumulation can counteract ROS, alleviating CI symptoms. In this sense, it has been confirmed that a brief hot-water (HW) immersion promotes the synthesis of antioxidants. RESULTS: HW treatment at 52 °C for 5 min significantly reduced chilling-associated decay, from 66.7% to 17.2% in breaker turning (BT) and from 55.8% to 9.8% in mature green (MG) 'BHN-602' tomatoes stored at 5 °C for 2 weeks and from 26.7% to 6.7% in BT tomatoes stored at 5 °C for 1 week. Also, HW treatment significantly increased lycopene content by 17% in BT tomatoes stored at 5 °C for 2 weeks, as well as ascorbic acid by 11%, lipophilic phenolics by 18% and total phenolics by 6.5% in BT tomatoes stored at 12.5 °C for 1 week. Despite the increase of antioxidants, HW treatment did not enhance the sensory aromatic profile, color and antioxidant capacity. Interestingly, HW treatment reduced ripening time by 3 days in MG tomatoes stored at 5 °C for 2 weeks or at 12.5 °C for 1 week. CONCLUSION: HW treatment applied to MG or BT 'BHN-602' tomatoes can alleviate the development of some CI symptoms, particularly decay, possibly by increasing antioxidants that scavenge ROS. © 2020 Society of Chemical Industry.

Phytochemical profiles, and antimicrobial and antioxidant activities of greater galangal [Alpinia galanga (Linn.) Swartz.] flowers.

Previous studies of galangal (Alpinia galanga) have focussed mostly on rhizomes but seldom on flowers. A comprehensive look at galangal flowers could reveal additional benefits. The chemical composition of galangal flowers was significantly (p < 0.05) different from that of galangal rhizome. Pentadecane and α-humulene were identified as major compounds of galangal flower essential oil. 1'-acetoxyeugenol acetate was identified as the highest compound in flowers and exhibited the strongest antimicrobial activity among all fractions, with MIC50 values of 34 µg/ml against Staphylococcus aureus and 68 µg/ml against Listeria monocytogenes. Galangal flowers had a 3-fold higher total phenols content than had rhizomes (10.5 vs. 3.33 mg GAE/g powder). The antioxidant activities of different flower fractions varied from 2 to 4.45 mmol  trolox/g phenolics. These findings suggest that antimicrobial and antioxidant agents extracted from galangal flowers could potentially be utilized as natural food preservatives or as therapeutic agents.

Fruit quality, nutraceutical and antimicrobial properties of 58 muscadine grape varieties (Vitis rotundifolia Michx.) grown in United States.

Fifty-eight muscadine grape varieties were evaluated for their fruit quality, nutraceutical, and antimicrobial properties during two growing seasons (2012 vs. 2013). Fruit quality was significantly different among muscadine grape varieties, with weight ranged from 2.93 to 22.32g, pH from 3.01 to 3.84, titratable acidity from 0.27% to 0.83%, and °Brix from 10.92 to 23.91. Total phenols for different muscadine juices varied from 0.26 to 1.28mgGA/mL, skins from 10.13 to 30.02mgGA/g DM, and seeds from 22.47 to 72.01mgGA/g DM. Accordingly, the antioxidant activity of grape juices varied from 0.97 to 6.78mmolTrolox/mL, skins from 83.59 to 221.20µmolTrolox/g DM, and seeds from 178.22 to 619.73µmolTrolox/g DM. Study demonstratedgrape seed polyphenols (MIC 54.8-60.1µg/ml) showed stronger antimicrobial activity against S. aureus than skin polyphenols (MIC 70.7-80.2µg/ml). This information could be a valuable asset in the research and extension of muscadine grapes.

Application of muscadine grape (Vitis rotundifolia Michx.) pomace extract to reduce carcinogenic acrylamide.

Acrylamide is a byproduct of the Maillard reaction and is formed in a variety of heat-treated commercial starchy foods. It is known to be toxic and potentially carcinogenic to humans. Muscadine grape polyphenols and standard phenolic compounds were examined on the reduction of acrylamide in an equimolar asparagine/glucose chemical model, a potato chip model, and a simulated physiological system. Polyphenols were found to significantly reduce acrylamide in the chemical model, with reduced rates higher than 90% at 100 µg/ml. In the potato chip model, grape polyphenols reduced the acrylamide level by 60.3% as concentration was increased to 0.1%. However, polyphenols exhibited no acrylamide reduction in the simulated physiological system. Results also indicated no significant correlation between the antioxidant activities of polyphenols and their acrylamide inhibition. This study demonstrated muscadine grape extract can mitigate acrylamide formation in the Maillard reaction, which provides a new value-added application for winery pomace waste.

Polyphenol oxidase inhibitor from blue mussel (Mytilus edulis) extract.

UNLABELLED: Enzymatic browning remains a problem for the fruit and vegetable industry, especially new emerging markets like pre-cuts. A crude inhibitor from blue mussel (Mytilus edulis) showed broad inhibition for apple (58%), mushroom (32%), and potato (44%) polyphenol oxidase (PPO) and was further characterized. Inhibition increased as the concentration of inhibitor increased in the reaction mixture eventually leveling off at a maximum inhibition of 92% for apple PPO. The inhibitor was capable of bleaching the brown color formed in the reaction mixture with apple PPO. Identification of the inhibitor by mass spectrometry and high-performance liquid chromatography revealed it to be hypotaurine (C2 H7 NO2 S). Hypotaurine and other sulfinic acid analogs (methane and benzene sulfinic acids) showed very good inhibition for apple PPO at various concentrations with the highest inhibition occurring at 500 µM for hypotaurine (89%), methane sulfinic acid (100%), and benzene sulfinic acid (100%). PRACTICAL APPLICATION: An inhibitor found in the expressed liquid from blue mussel shows very good inhibition on enzymatic browning. Since this enzyme is responsible for losses to the fruit and vegetable industry, natural inhibitors that prevent browning would be valuable. Finding alternative chemistries that inhibit browning and understanding their mode of action would be beneficial to the fruit and vegetable industries and their segments such as pre-cuts, juices, and so on. Inhibitors from products ingested by consumers are more acceptable as natural ingredients.

Fates of seeded Escherichia coli O157:H7 and Salmonella on selected fresh culinary herbs during refrigerated storage.

The fates of seeded Escherichia coli O157:H7 and Salmonella on selected fresh culinary herbs were evaluated at a refrigerated temperature (4 degrees C). Fresh herbs, including cilantro, oregano, basil, chive, parsley, and rosemary, were inoculated with six-strain mixtures of E. coli O157:H7 and Salmonella, and the microbial populations were monitored at 1, 5, 11, 16, 19, and 24 days. For both pathogens, a significant decrease in the population (P < 0.0001) occurred within the first 5 days of storage (< 0.8 log). Both pathogens remained the highest on cilantro and the lowest on rosemary (P < 0.0001). Storage time had a significant effect on the survival of E. coli O157:H7; populations declined as storage time progressed. Although storage of cilantro, basil, and chive was terminated after 19 days because of deteriorated quality, significant numbers of both pathogens were recovered from the remaining fresh herbs after 24 days of storage. The results showed that both bacteria were extremely persistent on all test herbs under the test conditions. The results also reinforce the concept that, once contaminated, bacterial pathogens can persist on fresh herbs throughout a normal distribution time.