Search

During 16 h heating at 180 °C, the oxidative stability (OS) of virgin olive oil (VOO) as affected by the same concentrations (200 ppm) of tertiary-butylhydroquinone (TBHQ) and unsaponifiable matters of bene kernel (UKO) and hull (UHO) oils in terms of the inhibitory effect on the formation of conjugated diene hydroperoxides (OS(CDV)) and off-flavor carbonyl compounds (OS(CV)) was investigated. TBHQ was not able to considerably increase the OS(CDV) (7.51) of the VOO (7.2) and showed no synergistic effect with indigenous antioxidative compounds of the VOO (IOV) in this respect. However, it could significantly improve the OS(CV) (from 2.49 to 4.52), which was mainly due to its synergism with the IOV. The UKO increased considerably the OS(CDV) (to 11.8), and its OS(CV) (4.22) was nearly the same as that of TBHQ. The IOV still had marked contributions to the prevention of VOO oxidation but the majority of stabilizing effect was related to the UKO and its synergism with the IOV. The OS(CDV) in presence of the UHO was less than that of the VOO (5.96), although it significantly increased the OS(CV) (to 5.2), mainly due to the stabilizing effect of UHO and its synergism with the IOV., (© 2012 Institute of Food Technologists®)

Unlabelled: Proanthocyanidins were extracted from peanut skins and investigated for their antimicrobial activity against Saccharomyces cerevisiae, Zygosaccharomyces bailii, and Zygosaccharomyces bisporus in traditional growth media (Sabouraud Dextrose and Maltose broth) and a simulated apple juice beverage. Peanut skins extracts (PSE) were prepared through a multisolvent extraction procedure. The PSE extended the lag phase growth of the 3 yeasts studied at a concentration of 1 mg/mL and at 10 mg/mL yeast growth was totally inhibited for 120 h. PSE was fractionated by normal phase high performance liquid chromatography and the active components/fractions were determined. Compounds present in the fractions were identified by liquid chromatography-mass spectrometry to determine the compounds responsible for inhibition. Fractions consisting mostly of A-type proanthocyanidin dimers, trimers, and tetramers showed the highest percent inhibition toward the yeasts tested in this study. Both optical density (OD) and standard enumeration plating methods were performed in this study. The OD method led to an overestimation of the inhibitory effects of PSE, the 2 methods agreed in respect to treatment effects but not the severity of the inhibition., Practical Application: There is a growing consumer demand for "fresh like" products containing reduced amounts of chemical preservatives without compromising food safety and quality. Therefore, the goal of this study was to determine if an extract of peanut skins containing flavonoid rich compounds could function as a natural antimicrobial in a model beverage system. Proteins were removed through the process of producing the peanut skin extract, thus it is unlikely to contain peanut allergens. The antimicrobial compounds mentioned in this study were successfully integrated into a model beverage system, and were found to have antimicrobial effect. However, the incorporation of these compounds would likely lead to negative sensory attributes at the concentration needed to achieve an appreciable antimicrobial effect alone., (© 2012 Institute of Food Technologists®)

Unlabelled: Escherichia coli O157:H7 and Salmonella spp. are bacterial pathogens often associated with beef, and cause many cases of foodborne illness each year in the United States. During beef slaughter and processing, these bacteria may spread from the hide or intestines to the carcass. The objective of this research was to investigate the use of naturally occurring compounds citrus essential oils (CEOs) extracted from orange peel to reduce or eliminate these pathogens at the chilling stage of processing, or during fabrication. Brisket flats (used to simulate beef subprimals) were spot inoculated with approximately 6 log of surrogate generic E. coli cocktail (previously shown to be identical in growth and survival parameters to E. coli O157:H7 and Salmonella spp.). Following drying, CEOs were applied by spraying at concentrations of 3% and 6% to the surface of different pieces of meat. Treatments were applied using a custom built spray cabinet at 2.07 bar and applied at a rate of 3.79 L/min to replicate commercial practices. The CEOs significantly reduced (P < 0.05) the concentration of E. coli on the brisket flats in comparison to inoculated no spray or water sprayed controls over a period of 90 d, while causing an initial reduction of approximately 1.4 log units. Total aerobic bacteria and psychrotrophic counts were also reduced on uninoculated briskets following treatment. These results indicate that 3% cold-pressed terpeneless Valencia orange oil could be used as an additional intervention against E. coli O157:H7 and Salmonella spp. at the refrigerated storage stage of processing., Practical Application: CEOs are natural compounds that have been designated as Generally Recognized as Safe (GRAS). They can be used to control Salmonella spp. and E. coli O157:H7 on beef carcasses at the chilling stage., (© 2011 Institute of Food Technologists®)

Unlabelled: The effect of calcinated calcium spray on Escherichia coli O157:H7 87-23 population reduction during radish sprout production was studied. Artificially inoculated radish seeds were soaked in sodium hypochlorite (NaOCl) solutions (200 and 20000 ppm), rinsed in distilled water, and sprayed with water or a calcinated calcium solution during sprouting. Microbial plate count was obtained at each step of the process and germination rate was determined after 72 h of sprouting. Scanning electron microscopy (SEM) was done on treated seeds and sprouts to locate which parts were populated by the E. coli cells. The results showed that the active compound in the calcinated calcium was calcium oxide. The treatment of 200 ppm NaOCl soaking followed by 0.04% calcinated calcium spray resulted in no microbial growth after a 72-h sprouting, while maintaining a high germination rate. The 0.4% calcinated calcium spray significantly reduced the germination rate and is therefore not recommended. Soaking the seeds in a 20000 ppm chlorine solution achieved the highest E. coli count reduction (1.65 log CFU/g). However, the E. coli cells that survived the 20000 ppm chlorine soak grew to 6 log CFU/g sprouts after a 72-h sprouting, significantly higher than the initial count on the seeds. The SEM microimages showed that the bacteria were mostly located in the roots of the radish sprouts and all across the seed surface. The E. coli O157:H7 87-23 cells appeared to be located in biofilms or embedded into the radish sprout tissues during sprouting., Practical Application: The seed sanitation treatment with 20000 ppm chlorine solution that is currently used by the sprout industry was once again found to be ineffective in eliminating inoculated pathogenic cells. More importantly, the remaining cells that have survived the chlorine wash would grow during sprouting to reach an alarmingly high cell concentration. The new observation of E. coli cells and sprout tissue interaction manifested as embedding of the cells in sprout tissues, if confirmed, will have a significant impact on the microbial safety intervention strategies used in the sprout industry. This research demonstrated the importance of eliminating all pathogens on the seeds before germination and sprouting., (© 2011 Institute of Food Technologists®)

The peptide mixture from housefly pupae has broad spectrum antimicrobial activity but has not previously been reported as a food preservative. In this study, the preservation effects of a housefly pupae peptide mixture, nisin, and sodium dehydroacetate (DHA-S) on the number of mesophilic aerobic bacteria (MAB), total volatile basic nitrogen (TVB-N), and pH value of chilled pork were compared. All results showed that a good preservation effect was observed among 3 treatments with the peptide mixture of housefly pupae, nisin, and DHA-S and that there was no significant difference among them. These results indicate that housefly peptide mixture has a great potential as a food preservative. The results of scanning electron microscope and transmission electron microscopy suggest that the primary mechanism of housefly pupae peptide mixture may be bacterial cytoplasmic membrane lysis and pores induced in the membranes. Practical Applications: Peptide mixture extracted from housefly pupae using low-cost and simple method has broad spectrum antimicrobial activity. According to the effect on chilled pork preservation, extracted housefly peptide mixture has a great potential as a food preservative.

The objectives of this study were to determine the frying stability of soybean oil (SBO) treated with a natural citric acid-based antioxidant, EPT-OILShield able to withstand high temperatures and to establish the oxidative stability of food fried in the treated oil. Soybean oil with 0.05% and 0.5% EPT-OILShield and an untreated control SBO were used for intermittent batch frying of tortilla chips at 180 degrees C for up to 65 h. Oil frying stability was measured by free fatty acids (FFA) and total polar compounds (TPC). Chips were aged for up to 4 mo at 25 degrees C and evaluated for rancid flavor by a 15-member, trained, experienced analytical sensory panel and for hexanal content as an indicator of oxidation. Oil with 0.05% EPT-OILShield had significantly less FFA and TPC than the control. The effect of EPT-OILShield was apparently retained in aged chips because hexanal levels were significantly lower in chips fried in oil with 0.05% EPT-OILShield than in chips fried in the control. Tortilla chips fried in the control were rancid after 2 mo at 25 degrees C at sampling times evaluated from 25 to 65 h; however, chips fried in oil with 0.05% EPT-OILShield and used for 65 h were described as only slightly rancid after 4 mo. Gamma tocopherol levels were significantly higher in the chips fried in the oil with 0.05% EPT-OILShield than in the control, helping to inhibit oxidation in the tortilla chips during storage.