Formulation, characterization, and stability of food grade oil-in-water nanoemulsions of essential oils of Tasmannia lanceolata, Backhousia citriodora and Syzygium anisatum

Oil-in-water nanoemulsions were formulated using sunflower oil mixed with each of the essential oils of Tasmannia lanceolata (Tasmanian pepper leaf [TPL]), Backhousia citriodora (lemon myrtle [LM]) and Syzygium anisatum (anise myrtle [AM]) and stabilized with Tween 80 using ultrasonication. An oil-surfactant ratio of 3:1 was found to produce the lowest emulsion droplet sizes of 96.6 nm for LM, 122.2 nm for AM and 131.8 nm for TPL. Increase in surfactant concentration above 10r resulted in larger droplet sizes, 165.8–2,647.2 nm for LM (radius, r =.82), 153.7–2,573.5 nm for AM (r =.93) and 157.4–2,621.6 nm for TPL (r =.83). Sonication for 3 min produced smaller droplet size; however, sonication for 9 min resulted in increase of droplet size by 1.48, 1.43 and 1.47 times for oils of LM (r =.82), AM (r =.93) and TPL (r =.83), respectively. A positive correlation was found between sonication amplitude (20–50%) and droplet size for nanoemulsions of LM (r =.93), AM (r =.98) and TPL (r =.95). TPL and LM nanoemulsions showed broad- spectrum antimicrobial activities against yeasts and bacteria. The minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) against weak-acid resistant yeasts were between 0.001–0.003 and 0.002–0.007 mg/ml for nanoemulsion of TPL and between 0.003–0.014 mg/ml and 0.005–0.027 for nanoemulsion of LM, respectively. The stability and antimicrobial activity of TPL and LM essential oil nanoemulsions confirm their potential for application as food preservatives especially in beverage products that are commonly spoiled by weak-acid resistant yeasts. © 2022 The Authors. Journal of Food Safety published by Wiley Periodicals LLC

Changes in quality and bioactivity of native food during storage

Australian native foods have long been consumed by the Indigenous people of Australia. There is growing interest in the application of these foods in the functional food and complementary health care industries. Recent studies have provided information on the health properties of native foods but systematic study of changes in flavour and health components during processing and storage has not been done. It is well known that processing technologies such as packaging, drying and freezing can significantly alter the levels of health and flavour compounds. However, losses in compounds responsible for quality and bioactivity can be minimised by improving production practices. This report outlines research developed to provide the native food industry with reliable information on the retention of bioactive compounds during processing and storage to enable the development of product standards which in turn will provide the industry with scientific evidence to expand and explore new market opportunities globally

Near infrared spectrometry for rapid non-invasive modelling of Aspergillus-contaminated maturing kernels of maize (Zea mays L.)

Open Access JournalAflatoxin-producing Aspergillus spp. produce carcinogenic metabolites that contaminate maize. Maize kernel absorbance patterns of near infrared (NIR) wavelengths (800–2600 nm) were used to non-invasively identify kernels of milk-, dough- and dent-stage maturities with four doses of Aspergillus sp. contamination. Near infrared spectrometry (NIRS) spectral data was pre-processed using first derivative Savitzky-Golay (1d-SG) transformation and multiplicative scatter correction on spectral data. Contaminated kernels had higher absorbance between 800–1134 nm, while uninoculated samples had higher absorbance above 1400 nm. Dose and maturity clusters seen in Principal Component Analysis (PCA) score plots were due to bond stretches of combination bands, CH and C=O functional groups within grain macromolecules. The regression model at 2198 nm separated uninoculated and inoculated kernels (p < 0.0001, R2 = 0.88, root mean square error = 0.15). Non-invasive identification of Aspergillus-contaminated maize kernels using NIR spectrometry was demonstrated in kernels of different maturities

Metabolites identified during varied doses of aspergillus species in Zea mays grains, and their correlation with aflatoxin levels

Open Access Journal; Published online: 7 May 2018Aflatoxin contamination is associated with the development of aflatoxigenic fungi such as Aspergillus flavus and A. parasiticus on food grains. This study was aimed at investigating metabolites produced during fungal development on maize and their correlation with aflatoxin levels. Maize cobs were harvested at R3 (milk), R4 (dough), and R5 (dent) stages of maturity. Individual kernels were inoculated in petri dishes with four doses of fungal spores. Fungal colonisation, metabolite profile, and aflatoxin levels were examined. Grain colonisation decreased with kernel maturity: milk-, dough-, and dent-stage kernels by approximately 100%, 60%, and 30% respectively. Aflatoxin levels increased with dose at dough and dent stages. Polar metabolites including alanine, proline, serine, valine, inositol, iso-leucine, sucrose, fructose, trehalose, turanose, mannitol, glycerol, arabitol, inositol, myo-inositol, and some intermediates of the tricarboxylic acid cycle (TCA—also known as citric acid or Krebs cycle) were important for dose classification. Important non-polar metabolites included arachidic, palmitic, stearic, 3,4-xylylic, and margaric acids. Aflatoxin levels correlated with levels of several polar metabolites. The strongest positive and negative correlations were with arabitol (R = 0.48) and turanose and (R = 0.53), respectively. Several metabolites were interconnected with the TCA; interconnections of the metabolites with the TCA cycle varied depending upon the grain maturity

Legumes as food ingredient: characterization, processing, and applications

Editores: Jiménez-López, José Carlos (CSIC); Clemente, Alfonso (CSIC

Effects of bifidogenic factors on growth of bifidobacterium bifidum in cultured milk yoghurt

Two Bifidogenic factors, pantethine and proteose peptone (which contains pantethine) promote survival and growth of Bifidobacteria at low pH (3.8-4.0) in cultured milk yoghurt. Cultures of milk containing pantethine (1.25, 2.5, 5, 10, 100 and 500 pg/100 mL of milk) and proteose peptone (250,500, 1000 mg/100 mL milk; equivalent to 2.5, 5 and 10 Hg pantethine) were inoculated with 5% (v/v) of Bifidobacterium bifidum strains P and Bl, fermented at 37°C and monitored until fermentation was complete. When strain Bl was grown in milk without bifidogenic factors it had a shorter fermentation time and the drop in pH to 3.8 was rapid compared to (3, a feature that is desirable in industry.Growth of Bl strain was observed when both pantethine and proteose pepetone were used, but the survival was better with pantethine. With proteose peptone, strain Bl showed rapid acidification of milk and growth