Renee Goodrich-Schneider

Use of Pulsed Ultraviolet Light to Reduce the Allergenic Potency of Soybean Extracts

Pulsed ultraviolet light (PUV), a non-thermal food processing technology, is reported to be able to inactivate enzymes and reduce allergen levels from peanut extracts. The objective of this study was to determine if PUV would reduce the allergen levels and allergenic potency of soy extracts. Soy extracts were treated with PUV at various times (2, 4 and 6 min), centrifuged, and analyzed by SDS-PAGE and an indirect ELISA for IgE binding or allergenic potency. Results showed that PUV treatment led to an increase in sample temperature/weight loss but a decrease in the levels of soy allergens (i.e., glycinin and ?-conglycinin) as shown in SDS-PAGE. Allergens were reduced probably through aggregation which increased with treatment time. IgE binding was reduced as well in the following order: 20%, 44% and 50% reductions in absorbance values at 2, 4, 6 min, respectively (the latter two were not significantly different (p < 0.05%) from each other). It was concluded that PUV was capable of reducing the allergenic potency of soy extracts, and that the optimal PUV treatment time was 4 min. Clinical data is still needed before PUV can find an application in the development of less allergenic soybean beverages and products.

Mitigation of Alicyclobacillus spp. spores on food contact surfaces with aqueous chlorine dioxide and hypochlorite.

The prevalence of Alicyclobacillus spp. and other spore-forming spoilage organisms in food handling and processing environments presents a sanitation challenge to manufacturers of products such as juices and beverages. The objectives of this study were to determine the efficacy of chlorine dioxide and sodium hypochlorite in killing Alicyclobacillus spores in situ and to evaluate the efficacy of various chlorine dioxide and hypochlorite sanitizing regimes on Alicyclobacillus spp. spores on stainless steel, wood, and rubber conveyor material. Five or two log CFU/ml spore concentrations were left in aqueous solution or inoculated onto stainless steel, rubber, or wood coupons and challenged with sanitizer for varied time intervals. After treatment, the coupons were placed in sterile sample bags, massaged with neutralizing buffer, and enumerated on Ali agar. Surfaces were also examined before and after treatment by scanning electron microscopy to confirm destruction or removal of the spores. For both five and two log CFU/ml spore concentrations, treatments of 50 and 100 ppm of chlorine dioxide and 1000 and 2000 ppm of hypochlorite, respectively, were the most effective. Of the range of chlorine dioxide concentrations and contact time regimes evaluated for all surfaces, the most effective concentration/time regime applied was 100 ppm for 10 min. Reductions ranged from 0 to 4.5 log CFU/coupon. Chlorine dioxide was least effective when applied to wood. Hypochlorite was not efficient at eliminating Alicyclobacillus spores from any of the food contact surfaces at any time and concentration combinations tested. Chlorine dioxide is an alternative treatment to kill spores of Alicyclobacillus spp. in the processing environment.

Conventional and Alternative Methods for Tomato Peeling

Peeling is one of the most important unit operations in tomato processing. Most recently, three novel tomato peeling methods were reported: infrared, ohmic heating and power ultrasound. Steam/hot water and lye peeling have been the most commercialized methods, but compared to steam peeling, lye peeling is more preferred and has gained widespread application among processors due to its association with higher product yields and better product quality. However, with the ever-tightening environmental protection laws, concerns have arisen in the recent years regarding lye usage as well as its disposal, which calls for alternative chemical-free peeling methods that can effectively peel the tomato while minimizing peeling losses and improving product quality. This review highlights the conventional methods used in tomato peeling, their efficacy and the potential applications of infrared, ohmic heating and power ultrasonics as a novel technology for tomato peeling.

Microbial decontamination of juices

Abstract: The microbiological concerns of juice decontamination historically involved prevention of spoilage. A number of Salmonella, Escherichia coli O157:H7, and Cryptosporidium parvum outbreaks associated with raw (unpasteurized) juices in the 1990s led to the introduction of regulation requiring 100% juice products be produced under a Hazard Analysis Critical Control Point (HACCP) program by the US Food and Drug Administration. This regulation requires that juice processors obtain at least a 5-log reduction of the ‘pertinent microorganism’ as a decontamination step. As a result of juice HACCP, most decontamination methods are measured to the 5-log reduction of the pertinent pathogen performance standard this regulation requires. In this chapter, outbreaks associated with juices will be summarized and we will discuss means by which microorganisms are eliminated in juices through both classical processing and novel methods for juice decontamination, what future trends in juice decontamination may be and provide further sources of information.

Measuring and Predicting Head Space Pressure during Retorting of Thermally Processed Foods

UNLABELLED Traditional metal cans and glass jars have been the mainstay in thermally processed canned foods for more than a century, but are now sharing shelf space with increasingly popular flexible pouches and semi-rigid trays. These flexible packages lack the strength of metal cans and glass jars, and need greater control of external retort pressure during processing. Increasing internal package pressure without counter pressure causes volumetric expansion, putting excessive strain on package seals that may lead to serious container deformation and compromised seal integrity. The primary objective of this study was to measure internal pressure build-up within a rigid air-tight container (module) filled with various model food systems undergoing a retort process in which internal product temperature and pressure, along with external retort temperature and pressure, were measured and recorded at the same time. The pressure build-up in the module was compared with the external retort pressure to determine the pressure differential that would cause package distortion in the case of a flexible package system. The secondary objective was to develop mathematical models to predict these pressure profiles in response to known internal temperature and initial and boundary conditions for the case of the very simplest of model food systems (pure water and aqueous saline and sucrose solutions), followed by food systems of increasing compositional complexity (green beans in water and sweet peas in water). Results showed that error between measured and predicted pressures ranged from 2% to 4% for water, saline, and green beans, and 7% to 13% for sucrose solution and sweet peas. PRACTICAL APPLICATION   Flexible packages have limited strength, and need more accurate and closer control of retort pressure during processing. The package becomes more flexible as it heats and might expand with increasing internal pressure that may cause serious deformation or rupture if not properly controlled and/or counterbalanced with external retort pressure. This article describes methods for determining exactly what the retort pressure profile will need to be to avoid this problem during retorting, and mathematical models to predict these pressures in response to known internal temperature and initial/boundary conditions.

Colorimetric Evaluation of Mahi-Mahi and Tuna for Biogenic Amines

ABSTRACT The Food and Drug Administration and National Marine Fisheries Services grade tuna and mahi-mahi using trained sensory panels in order to determine the quality of these fish. A major concern with both species is the presence of histamine in the flesh, which can cause scombroid poisoning, a severe illness that can lead to death. Three different assays were examined in an attempt to correlate sample grade with biogenic amine content. The first method, acetic acid Dräger tubes, was only effective in identifying the highest grade (lowest quality) of mahi-mahi. The second method was a bromophenol blue (BPB) colorimetric strip that was sensitive to volatile biogenic amines. The third method was a histamine-specific enzyme-linked immunosorbant assay (ELISA) that detected analytes in the liquid phase. The results of the BPB and ELISA methods showed a correlation between sample grade and biogenic amine content for mahi-mahi. The same correlation was not observed with the tuna samples, likely due to physiological differences between the two species that affect the detection of the analytes.

THE MATRIX EFFECT OF TUNA AND MAHI-MAHI ON BIOGENIC AMINE DETECTION

Method of standard addition (MSA) is used to account for and quantify matrix effect. In this study, MSA was used to analyze the matrix effect of mahi-mahi and tuna in respect to biogenic amine detection. Two different detection methods were used in conjunction with the MSA procedure: a colorimetric strip that detects volatile biogenic amines and a histamine-specific ELISA (enzyme-linked immunosorbant assay), which detects histamine in the liquid phase. Trained sensory experts were utilized to grade mahi-mahi and tuna. The grading system acted as a measure of fish quality. A biogenic amine cocktail was created to act as the standard spike for the MSA procedure. It contained histamine and other biogenic amine compounds of varying volatility that are present in nature. The ELISA-MSA showed a clear correlation between increase in histamine and a lower quality sample (higher numerical grade). The colorimetric strips did not have a clear correlation between biogenic amine content and grade. Comparing the two methods demonstrates that the matrix effect of the tuna and mahi-mahi is likely more prominent with gas phase compounds than liquid phase compounds.

Sensory evaluation and flavour analysis of soymilk produced from lipoxygenase-free soya beans after modified processes and pulsed light treatment

Conventional static pulsed light (PL) treatment completely inactivated lipoxygenase (LOX) in whole soya beans to prevent off-flavours produced by LOX. However, the produced soymilk had inadequate values for total solid content. The fully soaked treatment (FST) and shaking treatment (SHT) were best in terms of increasing total solid content of soymilk from 3.7% for control soymilk to 4.6% and 4.3%, respectively; therefore, these treatments were chosen for soymilk sensory evaluation. No significant statistical differences in sensory evaluation scores existed between the control and soymilk produced from FST. The SHT for 130 s had higher overall liking (4.8) and flavour (4.6) scores compared with the control (4.1 and 3.9, respectively). Flavour analysis (purge and trap GC-MS) of the soymilk revealed that the ethanol peak area was the biggest difference between the treatments. This study demonstrated soya beans treated with PL have no negative sensory effect in general. Producing lipoxygenase-free soya bean is an important achievement to enhance soyfood products because lipoxygenase catalyses lipid oxidation, which takes place when lipoxygenase is released during soy milling.

A Comparison of the Volatile Components of Cold Pressed Hamlin and Valencia (Citrus sinensis (L.) Osbeck) Orange Oils Affected by Huanglongbing

Volatiles from huanglongbing (HLB) symptomatic and asymptomatic cold pressed orange oils from Florida Hamlin and Valencia fruit were assessed. Qualitative gas-liquid chromatography studies showed the presence of several compounds (β-longifolene, perillene, and 4-decenal) which are not commonly identified in Citrus sinensis (L.) Osbeck oils. Oils derived from huanglongbing symptomatic fruit had lower concentrations of linalool, decanal, citronellol, neral, geranial, carvone, dodecanal, and 2-decenal and higher concentrations of citronellal compared to asymptomatic fruit. A comparison to historic literature of orange oil investigations before HLB was of issue in Florida orange crops showed lower levels of linalool, decanal, neral, and geranial in Hamlin peel oil samples, as well as higher levels of dodecanal. Valencia peel oil samples showed lower concentrations of linalool and increased concentration of citronellol and dodecanal. As a result of huanglongbing (HLB) phenomena, the concentrations of several important volatiles found in Hamlin and Valencia peel oil profiles have changed compared to historic values. Differences in volatile concentrations of symptomatic and asymptomatic HLB affected peel oil compounds in orange fruit are identified.

Inactivation of Lipoxygenase in Soymilk by Pulsed Light

Abstract Inactivation of soybean lipoxygenase in soymilk by pulsed light (PL) at different durations and distances from the pulsed light lamp was determined with and without ice surrounding the soymilk sample tray for cooling. The results show that without cooling, the lowest LOX residual activity was 0.37%, 0.00%, and 7.24%, and with cooling the LOX residual activity was 76.3%, 87.2%, and 69.0% for origin fluence of 302 J/cm2, 340 J/cm2, and 567 J/cm2, respectively. The LOX band reduced or disappeared after PL treatments compared with the LOX band control as assessed by electrophoresis. Peroxide value of the soymilk had no significant increase after pulsed light treatment. This research provided evidence that PL treatment could fully inactivate LOX in soymilk, mostly due to heat generated by the PL strobe, therefore the photo-thermal effect was the main factor that impacted LOX activity.