Impact of pulsed light treatments on antioxidant characteristics and quality attributes of fresh-cut apples

The effects of pulsed light (PL) treatments combined with a quality-stabilizing dip on the quality and antioxidant attributes of fresh-cut ‘Golden delicious’ apples was studied. Apple wedges were dipped into a solution of 1% w/v N-acetylcysteine and 0.5% w/v CaCl₂ and flashed with broad-spectrum light with an overall radiant exposure of 4, 8, 12 and 16 J^.cm⁻². General microbial counts, colour, firmness, phenolic compounds and vitamin C contents were evaluated over 15 days at 5 °C. More pronounced reductions of the naturally-occurring microbiota were observed as the applied PL-dose increased. The quality-stabilizing pre-treatment effectively prevented browning phenomena on the cut-tissue surface. In addition, browning and oxidation were not promoted in PL flashed samples. Indeed, the initial contents in phenolic compounds and vitamin C were even better maintained than in untreated samples. Treatments of 8 and 16 J cm⁻² were most effective for maintaining the quality and antioxidant characteristics.Industrial relevancePulsed light technology is an emerging technique with good prospects for the decontamination of foods and food contact surfaces. Application of pulse light treatments for increasing safety and extending microbial shelf life of fresh-cut produce seems feasible. However, their effects on the quality and antioxidant characteristics of fruit need to be evaluated for successfully applying the technology at an industrial level.     

Physical Properties of Food and Milk Components: Research Needs to Expand Uses

The physical properties of milk components affect the functional properties and quality attributes of foods in which they are used. Hence, knowledge of the basic physical properties of milk components is critical in determining the usefulness of milk components in food formulations and in determining quality attributes and acceptability of foods containing these components. Although much is known about the chemistry of milk components, fundamental data are limited regarding the physical properties that govern functionality and quality. This lack of information may limit potential uses of milk ingredients in the food processing industry.With the increasing formulation and fabrication of food products, the need and demand for reliable functional ingredients will expand. The food processing industry will increasingly place a premium on obtaining functional ingredients with reliable, well-defined physical and functional properties to facilitate automated formulation of food products and to ensure consistent product quality. Additionally, the satisfactory substitution of ingredients or simulation of traditional foods critically depends on knowledge of the physical properties of ingredients and of foods per se. Hence, there is a need for the establishment of a data bank that contains reliable information on the physical and functional properties of milk components and dairy ingredients. Where reliable data are not available, the needed research should be undertaken. In order to be successful in this endeavor, reliable, standardized testing methods need to be developed to measure those physical and functional properties related to quality attributes of foods.     

Principles and recent applications of novel non-thermal processing technologies for the fish industry—a review

Thermal treatment is a traditional method for food processing, which can kill microorganisms but also lead to physicochemical and sensory quality damage, especially to temperature-sensitive foods. Nowadays consumers’ increasing interest in microbial safety products with premium appearance, flavor, great nutritional value and extended shelf-life has promoted the development of emerging non-thermal food processing technologies as alternative or substitution to traditional thermal methods. Fish is an important and world-favored food but has a short shelf-life due to its extremely perishable characteristic, and the microbial spoilage and oxidative process happen rapidly just from the moment of capture, making it dependent heavily on post-harvest preservation. The applications of novel non-thermal food processing technologies, including high pressure processing (HPP), ultrasound (US), pulsed electric fields (PEF), pulsed light (PL), cold plasma (CP) and ozone can extend the shelf-life by microbial inactivation and also keep good sensory quality attributes of fish, which is of high interest for the fish industry. This review presents the principles, developments of emerging non-thermal food processing technologies, and also their applications in fish industry, with the main focus on microbial inactivation and sensory quality. The promising results showed great potential to keep microbial safety while maintaining organoleptic attributes of fish products. What’s more, the strengths and weaknesses of these technologies are also discussed. The combination of different food processing technologies or with advanced packaging methods can improve antimicrobial efficacy while not significantly affect other quality properties under optimized treatment.     

Thermal pasteurization of ready-to-eat foods and vegetables: Critical factors for process design and effects on quality

Increasing consumer desire for high quality ready-to-eat foods makes thermal pasteurization important to both food producers and researchers. To be in compliance with the Food Safety Modernization Act (FSMA), food companies seek regulatory and scientific guidelines to ensure that their products are safe. Clearly understanding the regulations for chilled or frozen foods is of fundamental importance to the design of thermal pasteurization processes for vegetables that meet food safety requirements. This article provides an overview of the current regulations and guidelines for pasteurization in the U.S. and in Europe for control of bacterial pathogens. Poorly understood viral pathogens, in terms of their survival in thermal treatments, are an increasing concern for both food safety regulators and scientists. New data on heat resistance of viruses in different foods are summarized. Food quality attributes are sensitive to thermal degradation. A review of thermal kinetics of inactivation of quality-related enzymes in vegetables and the effects of thermal pasteurization on vegetable quality is presented. The review also discusses shelf-life of thermally pasteurized vegetables.     

Nonthermal Processes for Shelf‐Life Extension of Seafoods: A Revisit

For the past two decades, consumer demand for minimally processed seafoods with good sensory acceptability and nutritive properties has been increasing. Nonthermal food processing and preservation technologies have drawn the attention of food scientists and manufacturers because nutritional and sensory properties of such treated foods are minimally affected. More importantly, shelf‐life is extended as nonthermal treatments are capable of inhibiting or killing both spoilage and pathogenic organisms. They are also considered to be more energy‐efficient and to yield better quality when compared with conventional thermal processes. This review provides insight into the nonthermal processing technologies currently used for shelf‐life extension of seafoods. Both pretreatments such as acidic electrolyte water and ozonification and processing technologies, including high hydrostatic pressurization, ionizing radiation, cold plasma, ultraviolet light, and pulsed electric fields, as well as packaging technology, particularly modified atmosphere packaging, have been implemented to lower the microbial load in seafood. Thus, those technologies may be the ideal approach for the seafood industry, in which prime quality is maintained and safety is assured for consumers.     

Processing effects for safety and quality in some non-predominant food technologies

Food functionality can be related to nutrient and non-nutrient compounds. Some foods are fortified with various nutrients whereas others are manipulated using their physicochemical properties in order to make them "functional." Texture, color, taste, odor, and other physicochemical properties may affect the overall quality and, hence, acceptance of food products. Since food safety is also an important factor to be considered in food processing, preservation methods are selected taking into account the best compromise between microbial inactivation and preservation of quality attributes. Instrumental and sensory methods, as well as a match between them, are studied and perfected in order to verify how well a specific type of food has been processed to make it "functional" in sensory terms.     

Superchilling of food: A review

Food preservation is very important for the safety and the reliability of the product. Superchilling as used for preserving foods, has been defined as a process by which the temperature of a food product is lowered to 1-2 °C below the initial freezing point. Fresh and high quality food products are in great demand worldwide. Temperature is a major factor determining the shelf life and quality of food products. Fish and meat are perishable food commodities, where better and more advanced preservation technology is needed. Deterioration of these foods mainly occurs as a result of chemical, enzymatic and bacteriological activities leading to loss of quality and subsequent spoilage. Storing food at superchilling temperature has three distinct advantages: maintaining food freshness, retaining high food quality and suppressing growth of harmful microbes. It can reduce the use of freezing/thawing for production and thereby increase yield, reduce energy, labour and transport costs. The study on the growth mechanism of ice crystals, modelling and computer simulation of foods during superchilling and superchilling storage is needed.     

Defining and characterizing the “nutty” attribute across food categories

The term “nutty” has been used to describe a vast array of foods including many foods outside the realm of nuts. However, it is not clear if “nutty” is a single term or if it takes various forms, depending on the type of product. The objective of this study was to determine whether a single nutty term could be used to describe nuttiness in all food products or if additional terms were needed. More than 200 products with potential nutty flavor, including nuts, nut spreads, grains/cereals, seeds, beans/legumes, oils, cheeses, fish, and beverages, were studied. Five “nutty” concepts were found and described with terms, definitions, and references with intensity ratings: overall nutty, nutty-beany, nutty-buttery, nutty-grain-like, and nutty-woody. Four of those attributes, excluding overall nutty, were single concept attributes that described subgroups of nuttiness. Specific terms, such as peanut or almond, that describe a certain type of nut but are separate from the “nutty” character were excluded intentionally because they do not describe nutty, they describe an overall concept flavor beyond nutty. A second panel of trained assessors was used to review the lexicon. This panel used this lexicon to describe a set of 10 products (nuts, grains, beans, seeds, cheeses) and determine if any additional attributes were needed to describe nuttiness. All of the products displayed varying intensities of the nutty attributes and the panel found no additional terms for the “nutty” component were needed. The development and verification of the lexicon has real-world application because it can assist in product development and quality assurance when describing foods with a “nutty” attribute. These terms can be applied across all food categories and is not exclusive to characterizing nuts.     

Sensory attribute preservation in extra virgin olive oil with addition of oregano essential oil as natural antioxidant

Four commercial varieties of oregano are farmed in Argentina: "Compacto,"Cordobes,"Criollo," y "Mendocino." Oregano essential oil is known for antioxidant properties. The objective of this study was to evaluate changes in the intensities of positive and negative attributes in extra virgin olive oil with addition of essential oil obtained from the 4 Argentinean oregano types. Oregano essential oil was added into olive oil at 0.05% w/w. The samples were stored in darkness and light exposure during 126 d at room temperature. The intensity ratings of fruity, pungency, bitterness, oregano flavor, and rancid flavor were evaluated every 21 d by a trained sensory panel. In general, samples with addition of oregano essential oil in olive oil exhibited higher and lower intensity ratings of positive and negative attributes, respectively, during storage compared with the control samples. The first 2 principal components explained 72.3% of the variability in the olive oil samples. In general, positive attributes of olive oil were highly associated with the addition of oregano essential oil in darkness, whereas rancid flavor was negatively associated with them. Olive oil with oregano "Cordobes" essential oil was oppositely associated with light exposure treatments and negative attribute (rancid flavor) suggesting better performance as natural antioxidant of this essential oil in olive oil. The result of this study showed that the presence of oregano essential oil, specially "Cordobes" type, preserve sensory quality of extra virgin olive oil prolonging the shelf life of this product. Practical Application: Extra virgin olive oil is highly appreciated for its health benefits, taste, and aroma. These properties are an important aspect in this product quality and need to be preserved. The addition of natural additives instead of synthetic ones covers the present trend in food technology. This research showed that the addition of oregano essential oil preserved the intensity ratings of positive attributes in extra virgin olive oil during storage. The essential oil of the oregano variety called "Cordobes" exhibited better protecting effect on sensory properties of olive oil than the other oregano varieties. The addition of oregano essential oil should be considered for the food industry as a natural source of antioxidant additives for preserving sensory properties in extra virgin olive oil and other similar food products.     

脉冲强光杀菌技术在食品保鲜领域的研究进展

近年来,细菌的耐药性逐年上升,食源性疾病爆发的频率也持续升高,为了提高食品的安全性并延长其货架期,非热杀菌技术在食品加工领域受到越来越多的关注。过去二十年中,人们对脉冲强光(Pulsed light,PL)进行了大量的研究,与热杀菌相比,脉冲强光具有安全、高效的特点,并能够更好地保留食品的色、香、味,特别是鲜切果蔬、肉类、鱼类等新鲜食品容易受到微生物的影响,但由于它们的敏感性,需要采取温和的杀菌措施。本综述主要总结近十年来脉冲强光杀菌技术在食品保鲜中一些新的研究发现,包括脉冲强光杀菌技术影响微生物灭活的因素和在食品保鲜领域的应用。     

A well balanced omega-6/omega-3 ratio in developing flax bolls after heating and its implications for use as a fresh vegetable by humans

Flax seed (Linum usitatissimum L.) can be used for both industrial and food products including a wide variety of nutraceuticals and health foods and for which a restricted and specific fatty acid (FA) profile is required. As functional foods, flax meal is provided to humans in the form of ground vacuum-packed grains or flaxseed-enriched baked products. However, no reports are yet available on the potential food use for fresh flax products. A comparative study was conducted using two flax cultivars, AC McDuff and Linola, to evaluate FA accumulation in developing bolls at 12 different developmental stages and to determine stages having well balanced omega-6/omega-3 FA ratio. The lipid hydroperoxide level in fresh bolls and seeds, and the cyanogenic glucoside content in developing bolls were also measured in AC McDuff following different heating treatments. The findings indicated and suggested that the use of flax bolls as health promoting vegetable can be considered if adequately processed and palatable food attributes are obtained.     

Microbial Inactivation and Quality of Guava and Passion Fruit Nectars Treated by UV-C Light

Freshness attributes in food products continue to be a trend of relevance to consumers. UV-C light treatment of fluid foods is a non-thermal process potentially suitable to obtain high-quality fruit nectars. This study pursued to test the effect of UV-C light treatment on indigenous microorganisms and sensory quality of two tropical fruit nectars. Guava and passion fruit nectars were treated with light at λ = 253.7 nm up to 24 and 11 J/ml, respectively, in an annular reactor. The effects of this process on microbial inactivation were assessed by aerobic mesophilic count (AMC), yeast and mould count (YMC) and by triangle tests regarding sensory quality. Microbial inactivation increased with fluence. The highest fluence decreased AMC of guava and passion fruit nectars by 0.51 and 1.36 log colony-forming units (CFU) per millilitre, respectively, and YMC of guava by 0.53 log CFU/ml. However, the sensory panel detected differences due to treatments even at the lowest fluences (15 and 6 J/ml for guava and passion fruit, respectively). This work confirms the capability of UV light to inactivate microorganisms in fluid foods, but in sensitive products such as tropical fruit nectars, sensory changes may be a drawback for practical application of the technology for producing fresh-like stable products.     

Recent Advances in Food Thawing Technologies

Serious quality deterioration can occur with suboptimal thawing, and thus innovative thawing technologies may have an important role in improving the final quality of frozen foods. In recent years, although several new thawing technologies have been extensively studied, such as ultra‐high pressure assisted thawing, ultrasound‐assisted thawing, high‐voltage electrostatic field thawing, ohmic thawing, and radio frequency thawing, more research is needed to make them more applicable to thawing of food industrially. A better evaluation of the impact of thawing is needed to help move new thawing technologies forward. This review discusses the principles involved, the applications to different types of foods, modeling of the various processes, new evaluation techniques, and patents obtained for the different systems. The benefits and weaknesses of these systems are also discussed to provide a more complete review of these new thawing techniques. This review will, hopefully, encourage additional work that may help reach the goal of having better food thawing systems.     

The silver sensory experience – A review of senior consumers’ food perception,liking and intake

It is commonly assumed that sensory impairments occurring with age negatively affect older people’s intake of foods in terms of both quality and quantity. This review discusses evidence published on the effects of age on sensory perception and the consequences for independently living seniors’ perception, liking and intake of food products. Because of anatomical changes in all the senses involved in human food perception, on average seniors perceive a lower flavour intensity than younger adults, are less sensitive to changes in the flavour profile of foods, and show a decreased ability to discriminate between different intensity levels of flavour and/or taste attributes. However, despite these differences in their sensory perception of foods, young adults and seniors seem to differ less in their initial hedonic appraisal of food products. Nonetheless, more research is needed to determine whether multisensory enrichment of foods across different modalities may lead to increased food liking in seniors both with and without olfactory impairment. Although limited, the current evidence suggests that sensory performance may be positively associated with BMI or body weight in specific senior populations. In addition, seniors fail to show a decreased appreciation of an eaten food, thereby increasing the risk of a monotonous diet. Taken together, these findings highlight the need for appropriate interventions and/or foods to improve and maintain adequate quantity and quality of food intake among independently living seniors, and especially those with low sensory performance. Such interventions should be holistic rather than focused on one modality and may also incorporate hedonic modulators such as past experiences, affective factors and external cues, e.g. brand names, labels or food packaging. In interventions and product development, segmentation of the senior consumer market is strongly advised to identify more homogeneous subgroups in order to deal with the large heterogeneity between independently living seniors. It is concluded that one size of the silver food experience will most likely not fit all senior consumers!     

Why do we like what we like?

Why do we find certain foods more pleasurable than others? Interactions of food components with human biology and with social and eating contexts give rise, in some predictable ways, to relatively stable individual food likes. While sensory and consumer research have traditionally focused on measuring existing likes, a better understanding of their basic determinants can provide ideas and tools to better predict and influence how likes may develop and change. The liking for a particular food or set of foods largely reflects the prevailing cultural environment and personal experiences, which generate variation in the opportunities and likelihood for specific biological predispositions and learning processes to operate with regard to particular foods. These learning processes may be largely influenced by the intrinsic orosensory or nutritional attributes of foods themselves, as well as characteristics of the situational contexts in which foods are experienced. Liking is one factor contributing to the desire to eat a food, and ultimately to food selection. Current knowledge of these processes is briefly reviewed, with suggestions of potential implications for understanding and predicting food acceptance and choice. © 2000 Society of Chemical Industry     

Pulsed Light Inactivation of Mushroom Polyphenol Oxidase: a Fluorometric and Spectrophotometric Study

Polyphenol oxidase (PPO) is one of the most important food enzymes; it is responsible for the browning of many foods. Pulsed light (PL) is a non-thermal method of food preservation that is able to inactivate PPO. The aim of this work was to gain insight into the mechanism of PPO inactivation by PL. To this, the kinetics of PPO inactivation by PL was measured, together with associated changes in tryptophan fluorescence, KI fluorescence quenching, and turbidity; and results were analyzed by parameter A and phase diagram methods. Enzyme inactivation followed the Weibull model. Tryptophan fluorescence decreased during PL treatment, as well as the parameter A, while Stern-Volmer constants increased and turbidity was constant. The phase diagram showed only two populated states. There was a high correlation between the loss of activity and parameter A. Results indicate that under the experimental conditions, the inactivation of PPO by PL is an all-or-none process where the enzyme progressively unfolds with no evidence of aggregation.     

Effect of high pressure thermal sterilization on the formation of food processing contaminants

The use of high pressure thermal sterilization (HPTS) as an emerging technology for the sterilization of foods could be a big turning point in the food industry. HPTS can result in a better overall food quality, lower thermal load applied to the product and less unwanted food processing contaminants (FPCs) as e.g. furan and monochloropropanediol/-esters.Hence, within the EU FP7 founded Prometheus-project HPTS treatments were performed for selected food systems. Therefore, two spore strains were tested, the Geobacillus stearothermophilus and the Bacillus amyloliquefaciens, in the temperature range from 90 to 121 °C at 600 MPa. The treatments were carried out in different fish system and ACES-buffer. The treatment at 90 and 105 °C showed that the G. stearothermophilus is more pressure sensitive than the B. amyloliquefaciens. The formation of FPCs was monitored during the sterilization process and compared to the amounts found in retorted samples of the same food systems. Depending on the food system the amounts of furan could be reduced between 71 and 97% for the tested temperature pressure combination even at sterilization conditions of F₀-value 7 min.Industrial relevanceThe high pressure thermal sterilization (HPTS) process is an emerging technology to produce high quality low acid food products, which are shelf-stable at ambient temperature. In addition the consumer today demands foods which are minimally processed and are healthy and safe. However, an industrial scale process has not yet been implemented.The work in this paper shows different temperature combinations (90 to 121 °C) at 600 MPa and their influence on the endospore inactivation and also on the formation of unwanted food process contaminants (FPCs), such as furan and monochloropropanediol/-esters, in comparison to retorting. The use of HPTS could lead to shorter process times and a means by which a better quality of the foods could be achieved.     

Capitalizing on a double crop: Recent advances in proso millet's transition to a food crop

Across the globe, strategies to adapt food production to a changing climate as well as to unforeseen events (such as a pandemic) are needed, for example, if farmers miss planting times due to abnormal weather patterns or harvests are lost. Such food security considerations represent reasons for why proso millet deserves a more prominent place at the table. It has one of the shortest growing seasons and water requirements among cereals and is already grown in rotation with other crops, for example, in the American Midwest. Yet, most consumers in the Western world are unfamiliar with it, which limits its market potential. Introducing proso millet to consumers requires development of products with acceptable textural and sensory attributes as well as convincing selling points. These can be found in its nutritional profile, as it is a gluten-free “ancient” grain and millet-based products frequently have low glycemic indices. This review presents a synthesis of recent studies that utilized processing strategies to advance proso millet functionality. Results are put into the context of the most frequently addressed compositional and functional attributes, organized in clusters. Diversity across varieties in amylose to amylopectin ratios presents an opportunity to utilize proso millet for foods with specific pasting requirements, as in bread versus pasta. Hydrothermal or pressure treatments may further adapt its functionality for baked goods. Bitterness remains an unsolved issue, even when decorticated material is used. In addition, heating dramatically lowers in vitro protein digestibility, whereas starch digestibility appears to be matrix dependent (more than raw material dependent).     

Predictors of food acceptance,consumption and satisfaction in specific eating situations

Three studies were conducted to examine the relationship of pre-test ratings of consumer food preferences (liking/disliking in response to a food name), expected liking/disliking, and situational appropriateness with post-test measures of liking/disliking, consumption and satisfaction in specific eating situations. A pre-test survey of 115 consumers assessed general preferences, expected liking/disliking, and appropriateness of 22 foods and beverages in 10 different use situations. The data showed a strong association between pre-test ratings of food appropriateness and expected liking/disliking. In the first experiment, subjects received an appropriate or inappropriate food at a lunch meal. In the second, subjects received a food item in either an appropriate or inappropriate social situation. Liking/disliking and consumption were poorly predicted from simple food preference measures. Better prediction was obtained by a combination of pre-test variables, but the variance accounted for was low. A likely factor influencing the results was the subjects' pre-test assumptions about the specific characteristics of the meal situation and how these matched or mismatched the actual meal conditions. In the third experiment, subjects received food items that varied in sensory quality at either an appropriate or inappropriate mealtime. In addition to the variables measured in Experiments 1 and 2, pre-test expected sensory attributes, post-test sensory attributes, judgments of whether the foods were “better or worse than expected” and “satisfaction” were collected. Results showed significant effects of both food quality and food appropriateness on all post-test variables, and confirmed the high degree of association between appropriateness and expected liking/disliking ratings found previously. Food preferences were again found to be poor predictors of post-test measures, while appropriateness and expected liking ratings were found to be good predictors of post-test appropriateness and food satisfaction ratings. Lastly, satisfaction was better predicted by both pre- and post-test variables than were either liking/disliking or consumption measures. Overall, the results show that the prediction of any aspect of consumer behavior toward foods in real life situations is extremely difficult. Although judicious use of multiple pre-test variables can improve prediction, much of the variability in liking, satisfaction, or consumption still remains unaccounted.     

Mechanisms for controlling enzymatic reactions in foods

Enzymes, as biocatalysts, are capable of specific manipulation of all the major biomolecules found in foods, and a wide variety of enzymes are therefore used as supplements for various food processing operations. There are, however, certain enzymes whose activities result in a rapid deterioration of food quality to be controlled in order to maintain quality and to extend product shelf‐life. Various mechanisms and techniques for controlling the undesirable activities of such enzymes in foods have been developed ingeniously over the years by food scientists. These include traditional methods like low‐ and high‐temperature treatment, chemical treatments, and control of water activity involving dehydration and salting. These techniques, however, have certain limitations, such as (1) changing the prime quality of certain foods, (2) health risks associated with certain chemical treatments, and (3) consumer preference for certain foods to be raw and “natural”. Novel and potentially viable techniques such as pressurization, use of enzymes (“killer enzymes”), ionizing radiation, chemical modification of enzymes, and other naturally occurring protein inhibitors have therefore been developed to help alleviate some of these problems.