In the last decade power ultrasound has emerged as an alternative processing option to conventional thermal approaches for pasteurisation and sterilisation of food products. While sonication alone ...may not be adequate for inactivation of various spoilage and harmful enzymes present in food, ultrasound in combination with mild heat treatment and/or pressure has shown potential for both enzyme and pathogen inactivation. Numerous studies have investigated ultrasound for inactivating enzymes such as pectinmethylesterase, polyphenoloxidases and peroxidases responsible for deterioration of fruit & vegetable juice and various enzymes pertinent to milk quality. The efficacy of ultrasound for the inactivation of enzymes in food is outlined in this review along with a description of the inactivation mechanism to elucidate the effect of ultrasound on important enzymes in fruit juices and dairy products.
The effects of sonication on pH, °Brix, titratable acidity (TA), cloud, browning index, and color parameters (L*, a*, and b*) of freshly squeezed orange juice samples were studied. Ultrasonic ...intensity (UI) levels of 8.61, 9.24, 10.16, 17.17, and 22.79 W/cm2 and treatment times of 0 (control), 2, 4, 6, 8, and 10 min were investigated. No significant changes in pH, °Brix, and TA (p < 0.05) were found. Cloud value, browning index, and color parameters were significantly affected by ultrasonic intensity and treatment time. Changes in cloud value followed first-order kinetics, whereas browning index, L*, a*, and b* values followed zero-order kinetics. Reaction rate constants were linearly correlated (R 2 > 0.90) to ultrasonic intensity.
Power ultrasound is recognised as a potential non-thermal technique to inactivate micro-organisms pertinent to fruit juices. In this study tomato juice was sonicated at different amplitude levels ...(24.4–61.0
μm) at a constant frequency of 20
kHz for treatment times (2–10
min) and pulse durations of 5
s on and 5
s off. Hunter colour values (
L∗,
a∗ and
b∗), pH, °Brix, titratable acidity, ascorbic acid and yeast inactivation were measured. No significant differences (
p
<
0.05) in pH, °Brix or titratable acidity were observed. Regression modelling was used to investigate the main effects of amplitude level and treatment time. Prediction models were found to be significant (
p
<
0.05) with low standard errors and high coefficients of determination (
R
2). Model predictions for critical quality parameters of Hunter colour values (
L∗,
a∗ and
b∗), ascorbic acid and yeast inactivation were closely correlated with the experimental results obtained.
Strawberry juice samples were sonicated at amplitude levels ranging from 40 to 100% at a constant frequency of 20 kHz for treatment times (2−10 min) and pulse durations of 5 s on and 5 s off. ...Sonication was found to reduce anthocyanin and ascorbic acid contents by 3.2 and 11%, respectively, at the maximum treatment conditions. Response surface methodology (RSM) based on a two-factor, five-level central composite design was employed to determine the effect of amplitude level and treatment time on anthocyanins (P3G), ascorbic acid (AA) content, and color values (L*, a*, and b*). The model predictions for the selected nutritional and quality parameters were closely correlated to the experimental results. RSM was demonstrated to be an effective technique to model the effect of sonication on strawberry juice quality while minimizing the number of experiments required.
Cold plasma technology is an efficient, environmental‐friendly, economic and noninvasive technology; and in recent years these advantages placed this novel technology at the centre of diverse studies ...for food industry applications. Dried food ingredients including spices, herbs, powders and seeds are an important part of the human diet; and the growing demands of consumers for higher quality and safe food products have led to increased research into alternative decontamination methods. Numerous studies have investigated the effect of nonthermal plasma on dried food ingredients for food safety and quality purposes. This review provides critical review on potential of cold plasma for disinfection of dried food surfaces (spices, herbs and seeds), improvement of functional and rheological properties of dried ingredients (powders, proteins and starches). The review further highlights the benefits of plasma treatment for enhancement of seeds performance and germination yield which could be applied in agricultural sector in near future. Different studies applying plasma technology for control of pathogens and spoilage micro‐organisms and modification of food quality and germination of dried food products followed by benefits and current challenges are presented. However, more systemic research needs to be addressed for successful adoption of this technology in food industry.
Grape juice samples were sonicated with processing variables of amplitude level (24.4–61.0
μm) and treatment time (0–10
min) at a constant frequency of 20
kHz and pulse durations of 5
s on and 5
s ...off. A full factorial experimental design with regression modeling was employed to investigate the main effects of amplitude level and treatment time on anthocyanins and color parameters. Significant effects of sonication on major anthocyanins cyanidin-3-O-glucosides (CA), malvanidin-3-O-glucosides (MA) and delphinidin-3-O-glucosides (DA), color values (
L*,
a*,
b*) and color index (CI) were observed. Prediction models were found to be significant (
p
<
0.05) with low standard errors and high coefficients of determination (
R
2). Model predictions for critical quality parameters of anthocyanins (CA; MA; DA), color values (
L*,
a*,
b*), TCD and CI inactivation were closely correlated to the experimental results obtained. Significant retention of anthocyanin content in grape juice was observed for CA (97.5 %); MA (48.2 %) and DA (80.9%) during sonication. CI and other color combinations (
L*
a*
b*,
L*
a*
/b* and
L*
b*
/a*) were found to be strongly correlated with anthocyanin content. This study shows that sonication could be employed for as a preservation technique for fruit juice processing where anthocyanin retention is desired.
Thermal imaging (TI) is an emerging, non-invasive process analytical technique suitable for the food industry. While TI was originally developed for military applications, it has recently emerged as ...a powerful non-destructive measurement technique in other industries. This paper provides an overview of TI theory, equipment, and image processing. Recent advances and potential applications of TI for food safety and quality assessment such as temperature validation, bruise and foreign body detection and grain quality evaluation are reviewed.
Consumer demand for safe and nutritious fruit juices has led to the development of a number of non thermal food preservation techniques. Recent research has highlighted the importance of anthocyanins ...in human health and nutrition. In this paper the effects of non thermal preservation technologies including high hydrostatic pressure, pulsed electric field, ultrasound, irradiation and ozone on the stability of anthocyanins are reviewed. The proposed mechanisms for degradation of anthocyanins during non thermal processing are also discussed along with potential factors to enhance their stability during processing and storage.
► Freeze drying may retain higher amount of phytochemicals than hot air drying of samples (carrot disks) ► Ultrasound assisted hot air dried samples may retain higher amount of polyacetylenes than ...blanched hot air dried carrot disks. ► Ultrasound treatment has the potential to replace blanching treatment, thus reducing the losses due to thermal treatment in food samples.
The effect of ultrasound and blanching pretreatments on polyacetylene (falcarinol, falcarindiol and falcarindiol-3-acetate) and carotenoid compounds of hot air and freeze dried carrot discs was investigated. Ultrasound pretreatment followed by hot air drying (UPHD) at the highest amplitude and treatment time investigated resulted in higher retention of polyacetylenes and carotenoids in dried carrot discs than blanching followed by hot air drying. Freeze dried samples had a higher retention of polyacetylene and carotenoid compounds compared to hot air dried samples. Color parameters were strongly correlated with carotenoids (
p
<
0.05). This study shows that ultrasound pretreatment is a potential alternative to conventional blanching treatment in the drying of carrots.
Application of ozone in grain processing Tiwari, B.K.; Brennan, C.S.; Curran, T. ...
Journal of cereal science,
05/2010, Letnik:
51, Številka:
3
Journal Article
Recenzirano
Ozone is an effective fumigant for insect killing, mycotoxin destruction and microbial inactivation which has a minimal or no effect on grain quality. Studies have demonstrated that ozone which is a ...natural agent, may offer unique advantages for grain processing along with addressing growing concerns over the use of harmful pesticides. This paper focuses on the efficacy of ozone for preservation of food grains and discusses the possible effects on product quality. Inactivation mechanisms for micro-organisms and mycotoxins are detailed. Critical intrinsic and extrinsic factors governing inactivation are discussed along with potential grain applications.
PDF
