Effect of soaking in noni (Morinda citrifolia) juice on the microbiological and color behavior of Haden minimally processed mango

Effects of Sonication and Thermal Pasteurization on the Nutritional, Antioxidant, and Microbial Properties of Noni Juice

Sonication is recognized as a potential food processing method to improve the functional properties of fruit juice. This study evaluated the effects of different sonication durations (20, 40, and 60 min) and thermal pasteurization on the nutritional, antioxidant, and microbial properties of noni juice. Fresh noni juice served as the control. The main organic acids detected were malic (57.54−89.31 mg/100 mL) and ascorbic (17.15−31.55 mg/100 mL) acids. Compared with the fresh sample, the concentrations of these compounds were significantly improved (p < 0.05) in the 60 min sonicated sample but reduced (p < 0.05) in the pasteurized sample. Moreover, sonication for 60 min resulted in increments of scopoletin, rutin, and vanillic acid compared to the fresh sample. The antioxidant activity of the juice sample was improved in the sample sonicated for 60 min. Irrespective of juice processing method, the level of microbial counts in noni juice was within the satisfactory level over the 8 weeks of refrigerated (4 °C) storage. This study highlights the feasibility of using ultrasound processing to enhance the quality of noni juice on the industrial scale.

Antibacterial Effect of Noni Juice In Vitro and Applied to Fresh-Cut Papaya to Control Escherichia coli O157 : H7

This study aimed to evaluate the effect of noni (Morinda citrifolia L.) juice (NJ) in vitro and applied it to fresh-cut papaya to control Escherichia coli O157 : H7. Furthermore, the NJ effect on the physicochemical characteristics of fresh-cut papaya was evaluated. We determined the minimal inhibitory concentration (MIC) in a microplate reader by the microdilution method using TSB using an initial concentration of 1 × 107 cells of E. coli/mL. Cubes of fresh-cut papaya fruit were immersed in an E. coli suspension (1 × 105 cells/mL) and after that in NJ three times (0, 2.5, and 5 min) and then stored at 4 ± 1°C for 18 days. The presence of E. coli and total coliforms, as well as pH, TSS, and titratable acidity, were evaluated every three days. The results of in vitro assays showed that NJ at 20% inhibited the microbial growth of E. coli, finding a maximum growth rate (μmax) of −0.0066 h−1. Immersion in NJ for 5 min presented a reduction of E. coli of 3.72 ± 1.43 log10 CFU/ $g$ of fresh-cut papaya fruit treated with this bacteria on day 9 of storage regarding control. Likewise, fresh-cut papaya fruit immersed in NJ for 5 min maintained the total coliforms between 1 and -1 log10 coliforms CFU/g for 18 days. However, the immersion treatment in NJ modified some physicochemical parameters of the fresh-cut papaya fruit, such as acidity and pH ( $P$  < 0.05). The application of NJ to fresh-cut papaya fruit showed in vitro and in vivo inhibition of E. coli and total coliforms, evidencing it as a possible bacterial control agent in the precut fruit industry for up to 18 days.

Antibacterial activity of the noni fruit extract against Listeria monocytogenes and its applicability as a natural sanitizer for the washing of fresh-cut produce

This study was conducted to investigate the antibacterial activity of the noni fruit extract (NFE) against Listeria monocytogenes (ATCC, 19111 and 19115) and assess its applicability for the washing of fresh-cut produce. Based on the results of the disc diffusion test, L. monocytogenes (ATCC, 19111 and 19115) was susceptible to the activity of NFE than other pathogens studied. Additionally, results of the time-kill assay indicated that NFE at a concentration of 0.5-0.7% effectively killed L. monocytogenes within 7 h. Furthermore, analysis of the intracellular components such as nucleic acids and proteins released from the bacterial cells and their SEM imaging revealed that NFE could increase the membrane permeability of cells resulting in their death. Compared to their unwashed samples, washing of romaine lettuce, spinach, and kale with 0.5% NFE gave a reduction of 1.47, 2.28, and 3.38 log CFU/g, respectively against L. monocytogenes (ATCC, 19111 and 19115), which is significantly different to that of NaOCl. A significant correlation was observed between the antibacterial effect induced due to NFE washing with the surface roughness of the fresh-cut produce than its surface hydrophobicity. Moreover, washing with NFE was not found to affect the color of the samples. These results indicated that NFE demonstrates good antibacterial activity against L. monocytogenes and can be used as a natural sanitizer to ensure the microbiological safety of fresh-cut produce.

One Plant, Many Uses: A Review of the Pharmacological Applications of Morinda citrifolia

Morinda citrifolia, also known as noni, is commonly used in popular medicine in Brazil. Many parts of the noni tree are utilized in such practices, including the roots, leaves and seeds. Through a search of online databases, the present article reviews 92 research studies on the biological actions of M. citrifolia. The paper will discuss the therapeutic effects of noni and its compounds in a variety of forms of presentation, focusing on studies that support its traditional use. A large and diverse number of properties were identified, which were divided into immunostimulatory, antitumor, antidiabetic, anti-obesity, antibacterial and anti-septic, antifungal, antiviral, leishmanicidal, antiinflammatory, antinociceptive and analgesic, antioxidant, neuroprotective, wound healing, antiallergic, antiangiogenic, antiemetic and anti-nausea, anti-gastric ulcer and oesophagitis, anthelmintic, antimutagenic, antipsychotic, anxiolytic, photoprotective, anti-wrinkle and periodontal tissue regeneration activities. While it was concluded that although M. citrifolia is widely and successfully used for the treatment or prevention of various diseases, it should be consumed carefully, and only after exhaustive studies into its chemical constituents and mechanisms of action, both in in vitro and in vivo models, as well as clinical trials. Copyright © 2017 John Wiley & Sons, Ltd.