Effect of pre-harvest and post-harvest conditions on the fruit allergenicity: A review.

Fruits are an important source of vitamins and antioxidants that can effectively delay aging and contribute to health and well-being of the human kind. However, they are growing to be one of the primary elicitors of food allergies around the world. Fruit allergens can induce an IgE-mediated (Immunoglobulin E) reaction, presenting with a symptom like localized oral allergy syndrome (OAS). Numerous studies showed that varying environmental and cultivation conditions can influence the fruit allergen content during flowering and ripening stages. Further, the variety, harvesting maturity, and storage conditions can also significantly influence the allergenicity potential. For example, unripe apples and tomatoes have lower levels of allergens compared to ripened fruits. Researchers have also reported that modified atmosphere packaging (MAP) can help reduce Mal d 3 content present in apples during storage. Post-harvest processing like peeling is also considered a good method to help reduce the overall allergenicity in few fruits whose peel might contain majority of the allergens. This review will discuss the overall influence of both pre-harvest and post-harvest factors on the fruit allergens. We will also discuss the progress regarding the cause, symptoms and diagnostic methods of fruit based allergies.

A Comprehensive Review on Kiwifruit Allergy: Pathogenesis, Diagnosis, Management, and Potential Modification of Allergens Through Processing.

Kiwifruit is rich in bioactive components including dietary fibers, carbohydrates, natural sugars, vitamins, minerals, omega-3 fatty acids, and antioxidants. These components are beneficial to boost the human immune system and prevent cancer and heart diseases. However, kiwifruit is emerging as one of the most common elicitors of food allergies worldwide. Kiwifruit allergy results from an abnormal immune response to kiwifruit proteins and occur after consuming this fruit. Symptoms range from the oral allergy syndrome (OAS) to the life-threatening anaphylaxis. Thirteen different allergens have been identified in green kiwifruit and, among these allergens, Act d 1, Act d 2, Act d 8, Act d 11, and Act d 12 are defined as the "major allergens." Act d 1 and Act d 2 are ripening-related allergens and are found in abundance in fully ripe kiwifruit. Structures of several kiwifruit allergens may be altered under high temperatures or strong acidic conditions. This review discusses the pathogenesis, clinical features, and diagnosis of kiwifruit allergy and evaluates food processing methods including thermal, ultrasound, and chemical processing which may be used to reduce the allergenicity of kiwifruit. Management and medical treatments for kiwifruit allergy are also summarized.

Application of molecular dynamic simulation to study food proteins: A review.

This review presents an overview of the application of molecular dynamic simulation to study food proteins. Processing of food using thermal, chemical, radiation, electromagnetic, and mechanical techniques is subject to its macromolecular bio-components such as carbohydrates and proteins to extreme heat, ionic strength, pH, and mechanical deformation. These processing factors affect protein's functional properties such as emulsification, dough formation, gelation, etc., which are associated with changes in their structure. It is difficult to study the structural changes of protein during processing using standard methods like Circular dichroism, Nuclear Magnetic Resonance (NMR), and X-ray diffraction. Hence, in this manuscript application of molecular dynamic simulation to visualize and analyze the protein dynamics during processing has been evaluated. Effect of external stresses such as hydration, temperature, and electric field on protein structure have been analyzed and related mechanisms are explained. The response of food proteins to these stresses demonstrated that it is necessary to gain insight into protein dynamics to be able to develop novel and/or modify existing food processing techniques to improve the overall nutritional and organoleptic qualities of processed food products.

How well do plant based alternatives fare nutritionally compared to cow's milk?

Due to the issues like lactose intolerance and milk allergy arising from the consumption of cow's milk, there has been an increased demand in the plant based alternative milks around the world. Food industry has addressed these demands by introducing various milk beverages which are promoted as alternatives coming from plant sources which include almond milk and soy milk. Though they are popularly advertised as healthy and wholesome, little research has been done in understanding the nutritional implications of consuming these milk beverages in short term and long term. Further, consumers associate these alternatives to be a direct substitute of cow's milk which might not be true in all cases. This review tries to address the issue by outlining the differences between cow's milk and commercially available alternative milks in terms of their nutrient content. Though various plant based alternate milks have been studied, only the four most consumed milk beverages are presented in this review which are consumed widely around the world. A complete nutritional outline and the corresponding health benefits of consuming these plant based milk beverages have been discussed in detail which could help the consumers make an informed decision.

Review of conventional and novel food processing methods on food allergens.

With the turn of this century, novel food processing techniques have become commercially very important because of their profound advantages over the traditional methods. These novel processing methods tend to preserve the characteristic properties of food including their organoleptic and nutritional qualities better when compared with the conventional food processing methods. During the same period of time, there is a clear rise in the populations suffering from food allergies, especially infants and children. Though, this fact is widely attributed to the changing livelihood of population in both developed and developing nations and to the introduction of new food habits with advent of novel foods and new processing techniques, their complete role is still uncertain. Under the circumstance, it is very important to understand the structural changes in the protein as food is processed to comprehend whether the specific processing technique (conventional and novel) is increasing or mitigating the allergenicity. Various modern means are now being employed to understand the conformational changes in the protein which can affect the allergenicity. In this review, the processing effects on protein structure and allergenicity are discussed along with the insinuations of recent studies and techniques for establishing a platform to investigate future pathway to reduce or eliminate allergenicity in the population.

Processing effects on tree nut allergens: A review.

"Tree nut" is a broad term for classification of nuts that include cashews, almonds, hazelnuts, etc. Reports of mild to adverse immune reactions following the consumption of these nuts has been on a rise in recent years. Currently, about 1.2-2% of the world's population suffer from sensitivity to tree nuts. The only solution is complete abstinence from the allergy causing tree nut which is not feasible in most cases due to issues like cross contamination or their presence in the form of hidden ingredients in processed foods. Various studies have shown that food processing can effectively vary the secondary structures of the allergenic protein which in turn influences their functional properties. But, the impact of these processing methods on tree nuts allergens is mixed. This review gives an update on the recent findings on how conventional and novel processing methods influence the tree nut allergens.

Effect of microwave processing on the nutritional properties and allergenic potential of kiwifruit.

Kiwifruit is an excellent source and has highly drawn attention due to its essential nutrients and health benefits. However, kiwifruit can trigger allergenic symptoms and cause health problems worldwide. This study aimed to evaluate the impact of microwave processing on the nutritional properties and allergenicity of kiwifruit. Samples were treated with microwave at 75 â„ƒ for 0-5 min. The microstructure, color attributes, allergen (Act d 2) content, in vitro digestibility, and secondary structure of kiwifruit protein were determined. The results found that microwave processing significantly increased the total antioxidant activity by disrupting the microstructure of kiwifruit tissues. The digestibility and peptide content of kiwifruit protein was improved. Whereas a negative effect on the color attributes and sugar content was observed. An 80 % reduction in Act d 2 content was observed after a 5-min microwave treatment. Therefore, microwave processing showed a potential application in reducing kiwifruit allergenicity.

Effects of Microwaves, Ultrasonication, and Thermosonication on the Secondary Structure and Digestibility of Bovine Milk Protein.

Cow's milk is considered an excellent protein source. However, the digestibility of milk proteins needs to be improved. This study aimed to evaluate the relationship between the functional properties of milk proteins and their structure upon microwave, ultrasound, and thermosonication treatments. The protein content, digestibility, and secondary-structure changes of milk proteins were determined. The results demonstrated that almost 35% of the proteins in the untreated samples had a α-helix structure and approximately 29% a ß-sheet and turns structure. Regarding the untreated samples, the three treatments increased the α-helices and correspondingly decreased the ß-sheets and turns. Moreover, the highest milk protein digestibility was observed for the ultrasound-treated samples (90.20-94.41%), followed by the microwave-treated samples (72.56-93.4%), whereas thermosonication resulted in a lower digestibility (68.76-78.81%). The milk protein content was reduced as the microwave processing time and the temperature increased. The final milk protein available in the sample was lower when microwave processing was conducted at 75 °C and 90 °C compared to 60 °C, whereas the ultrasound treatment significantly improved the protein content, and no particular trend was observed for the thermosonicated samples. Thus, ultrasound processing shows a potential application in improving the protein quality of cow's milk.

Structural responses of kiwifruit allergen Act d 2 to thermal and electric field stresses based on molecular dynamics simulations and experiments.

Kiwifruit is considered to be the most common plant-based food causing allergic reactions, after peanuts, soybeans, and wheat. These responses are triggered by the proteins in kiwifruit. Modifying the structures of these allergenic proteins (epitopes) through external stresses may decrease their specific binding capacity with antibodies, resulting in a decrease in kiwifruit allergenicity. To provide a visual insight into the structural changes of Act d 2, we treated it with a thermal force and an oscillating electric field using molecular dynamics (MD) simulations. The results showed that Act d 2 is a heat-stable protein, while the electric field combined with thermal stress significantly affected its secondary structure and surface properties, which could result in conformational changes. The results obtained from ELISA tests showed that the combination of the thermal force and electric field significantly reduced the Ig-E binding capacity of Act d 2 by 75.3%, accompanied with obvious losses of alpha-helix and turn structures.

Effect of pulsed ultrasound, a green food processing technique, on the secondary structure and in-vitro digestibility of almond milk protein.

In recent years, almond has been considered as one of the most common alternative plant-based protein sources due to its nutritional attributes and health benefits. However, almond protein has a lower digestibility compared with the animal protein. The objective of this study is to investigate the impact of pulsed high-intensity ultrasound on the secondary structure of the almond protein. The changes in the in-vitro protein digestibility (IVPD %) are also evaluated to investigate the relationship between the structure and digestibility of the almond protein. The secondary structures were analyzed using Fourier-transform infrared spectroscopy (FT-IR) and circular dichroism (CD) spectroscopy. FT-IR analysis showed a slight relocation in the ordered and unordered structures in the ultrasonicated almond protein compared to the control. CD spectroscopy revealed that ultrasound resulted in the restructuring of α-helices into ß-sheets. However, upon treating the almond protein for 16 min, a slight recovery in α-helices was observed. Moisture content was found to affect the secondary structure orientations of almond protein significantly. Although the IVPD% change was not statistically significant, it was found to be increasing slightly with processing duration and was dependent on protein secondary structure.

High-intensity ultrasound processing of kiwifruit juice: Effects on the microstructure, pectin, carbohydrates and rheological properties.

This study aimed to evaluate the influences of high-intensity ultrasound on the physiochemical properties of kiwifruit juice. Results reported high-intensity ultrasound processing significantly enhanced the color attributes, cloudiness, and sugars of kiwifruit juice. Further, the shear stress, apparent viscosity, storage and loss modulus was increased with the rise of processing time. However, a significant degradation in the nanostructure of water-soluble pectin and suspended particles in ultrasound treated kiwifruit juice was observed. In addition, ultrasound processing resulted in the rupture of cell wall causing the dispersion of the intracellular components into juice while higher damage in the cellular structure was observed by increasing the processing time. These structural changes reveal the physical mechanism of ultrasound in improving the rheological properties, color attributes, cloudiness, and water-soluble pectin of kiwifruit juice. Altogether these findings suggest that high-intensity ultrasound has an enormous potential to improve the physical properties of kiwifruit juice.

Effect of thermal and microwave processing on secondary structure of bovine ß-lactoglobulin: A molecular modeling study.

Milk allergy is known to cause severe allergic reactions in hypersensitive patients, especially in infants and children. ß-Lactoglobulin is one of the major allergens in bovine milk. The influence of thermal and microwave processing on the structural deviations of ß-lactoglobulin protein have been studied using molecular modeling techniques. The structural deviations are studied using root mean square deviations, radius of gyration, dipole moment, and solvent accessible surface area. STRIDE analysis showed significant changes in the ß-lactoglobulin, especially when oscillating electric fields were applied along with heat. Root mean square fluctuations (RMSF) has been assessed for known epitopes in the ß-lactoglobulin molecule. This showed that when the protein is exposed to certain thermal stress, it compacts by burying hydrophobic residues in the core. However, few allergic epitope residues also exhibit increased RMSF leading to higher reactive sites on the surface of the protein molecule. PRACTICAL APPLICATIONS: This study showed that molecular modeling can be used to gain valuable insights regarding the structural changes during processing. In the future, with more computational capacity, it can be used to make comparison between results obtained from simulations and real-time experiments. The current techniques used in food industries such as Nuclear Magnetic Resonance Imaging, Fourier Transformation Infrared Spectroscopy, X-ray diffraction can analyze pre- and post-processing effects. Hence, it become necessary to understand the changes that takes place during the processing techniques. Molecular dynamic simulation could be a useful technique in analyzing the changes occurring during the processing.

Simulations of Temperature and Pressure Unfolding in Soy Allergen Gly m 4 Using Molecular Modeling.

This study aims at understanding the changes in the structural properties of Gly m 4 soy allergen as a result of the influence of the temperature and pressure deviations. The primary emphasis was placed on analyzing the surface properties of suspected linear and conformational epitopes present in the Gly m 4 allergen. All three epitopes of Gly m 4 were studied, and the results showed that the molecule has significant structural changes in terms of solvent-accessible surface area (SASA) and radius of gyration, which showed that the increased pressures resulted in compaction. However, at lower temperatures and higher pressures (300 K and 6 kbar), swelling in the molecule was observed with a significant increase in the surface area. The study also tracked the changes in surface areas of individual residues that are part of the selected epitopes. Residues, such as D-27 and T-51, were found to have significant changes in their SASA as a result of temperature and pressure deviations.

Comparison of Conventional and Microwave Treatment on Soymilk for Inactivation of Trypsin Inhibitors and In Vitro Protein Digestibility.

Soymilk is lower in calories compared to cow's milk, since it is derived from a plant source (no cholesterol) and is an excellent source of protein. Despite the beneficial factors, soymilk is considered as one of the most controversial foods in the world. It contains serine protease inhibitors which lower its nutritional value and digestibility. Processing techniques for the elimination of trypsin inhibitors and lipoxygenase, which have shorter processing time and lower production costs are required for the large-scale manufacturing of soymilk. In this study, the suitable conditions of time and temperature are optimized during microwave processing to obtain soymilk with maximum digestibility with inactivation of trypsin inhibitors, in comparison to the conventional thermal treatment. The microwave processing conditions at a frequency of 2.45 GHz and temperatures of 70 °C, 85 °C and 100 °C for 2, 5 and 8 min were investigated and were compared to conventional thermal treatments at the same temperature for 10, 20 and 30 min. Response surface methodology is used to design and optimize the experimental conditions. Thermal processing was able to increase digestibility by 7% (microwave) and 11% (conventional) compared to control, while trypsin inhibitor activity reduced to 1% in microwave processing and 3% in conventional thermal treatment when compared to 10% in raw soybean.

Effect of MW-assisted roasting on nutritional and chemical properties of hazelnuts.

In order to enhance the flavor, texture, color, and appearance of hazelnuts, they are roasted during postharvest processing. In this study, raw hazelnuts (Corylus avellana L.) were roasted using microwave (MW) and MW-assisted hot air methods under various roasting conditions. The hazelnuts roasted were then examined to determine the percent DPPH radical scavenging activity, antioxidant capacity, total phenolic content, resistant starch, non-resistant starch, total starch, and protein concentration. The roasting experiments were done using a completely randomized factorial arrangement of two roasting types by three roasting times (9, 15, and 21 min) by three roasting temperatures (70, 90, and 110°C) using three replications within each experiment. These roasting methods were found to yield significant differences in antioxidant capacity, total phenolic content, resistant starch, non-resistant starch, and protein concentration between MW and MW-assisted hot air roasting processes, while no difference was found in percent DPPH radical scavenging activity and total starch. The results obtained may be of great importance to the food research community and industrial hazelnut roasting technologies.