Effects of fruit bagging on anthocyanins, sugars, organic acids, and color properties of ‘Granny Smith’ and ‘Golden Delicious’ during fruit maturation

The effects of fruit bagging on anthocyanins, sugars, organic acids, and color properties of ‘Granny Smith’ and ‘Golden Delicious’ were investigated in this study. Young fruits were bagged 40 days after flowering (DAF) with paper bags. The bagged fruits of ‘Golden Delicious’ were uncovered and exposed to light 120 DAF, while those of ‘Granny Smith’ 160 DAF. The fruits were harvested after 0, 2, 4, 6, 8, 10, and 15 day of bag removal, respectively. The development of anthocyanins, sugars, organic acids, and color properties in the flesh of ‘Granny Smith’ and ‘Golden Delicious’ was determined. After bag removal, the ‘Granny Smith’ and ‘Golden Delicious’ turn red, a* was consequently augmented, while L*, b*, C*, and h⁰ reduced. Cyanidin 3-galactoside and cyaniding 3-arabinoside were identified in ‘Granny Smith’ and ‘Golden Delicious’ as the two constituents responsible for red color of apple peel, and with cyanidin 3-galactoside being the most abundant anthocyanin in these non-red cultivars. Fructose, sucrose, and sorbitol were the major sugars and sugar alcohol, and malic acid was the major organic acid. Concentrations of most sugars and all organic acids quickly increased during 0–4 DABR, suggesting that synthesis of these sugars and organic acids was inhibited by fruit bagging. Furthermore, the cy3-gal and cy3-ara accumulation of all tested cultivars was significantly correlated with sucrose, indicating that sucrose may be the more important factors in the biosynthesis of anthocyanin.     

Effects of gamma irradiation dose and short-term storage on phytochemicals,antioxidants, and textural properties of boiled ‘Tainan 9’ peanuts

Boiled peanuts are preferable as a ready-to-eat healthy snack; however, gamma irradiation as a postharvest treatment of raw peanuts may induce unfavourable food components. Hence, the phytochemical, antioxidant, and the texture of boiled ‘Tainan 9’ peanuts pretreated with gamma irradiation (0, 2.5, 5, and 10 kGy) and stored at 29 ± 2 °C for up to 180 days were investigated. Both gamma irradiation and storage time contributed to testa darkening in raw peanuts. In boiled irradiated products, irradiation doses and storage time affected the moisture content (MC), total proteins, total oil, total soluble sugars, and antioxidant capacity (P ≤ 0.05). Total phenolic and flavonoid contents showed an increase at days 90 and decreased at days 180 across all treatments. A positive correlation was observed among ferric reducing antioxidant power (FRAP), total phenolics, and total flavonoids. Gamma irradiation at 10 kGy led to increase of peroxide value (PV) (P ≤ 0.05), but malondialdehyde (MDA) content was unaffected. Textural properties of boiled irradiated peanuts were soft. As a result, gamma irradiation at 5 kGy is recommended for postharvest treatment of raw peanuts with subsequent storage up to 180 days to obtain the eating quality of boiled peanuts with good phytochemicals and antioxidant properties, which is a challenge for food industry.     

Paired preference tests: ‘Liking’, ‘Buying’ and ‘Take Away’ preferences

Paired preference tests of liking require consumers to specify which of two foods are preferred or whether there is no preference. For ‘Buying’ preference tests, consumers specify which of two foods they are more likely to buy or whether there is no operational difference in likelihood to buy. The former test is designed to predict choice behaviour, the latter, buying behaviour. To validate the predictive ability of such tests, consumer choice and buying behaviour should be observed for several months. Another approach is to allow consumers to take away some of the foods used in the test and observe what they take. Consumers of potato chips were required to taste chips whose flavour and appearance were obviously different. A first group (N = 109) were given a traditional paired preference test of liking. A second group (N = 108) were given a preference test of buying. A third group (N = 101) were given both tests. After the test, out of sight of the experimenter, consumers were presented with two rows of plain plastic ‘snack’ bags, filled with the chips used in the test. They could take away either two bags of the same type of chip (a ‘Take Away’ preference) or one of each type (no ‘Take Away’ preference) or take neither (rejection). ‘Liking’ preferences predicted what was taken away for only 48% of consumers for the first group and 45% (third group). For ‘Buying’ preferences, the correspondence was 56% (second group) and 60% (third group). Using buying tests separately or together with liking produced some differences. More reliably, approximately 60% of consumers in all groups chose one bag of each. ‘Take Away’ preferences suggested low predictability for paired preference tests of liking and buying. ‘Take Away’ preferences are not a substitute for following a consumer for several months but they are a step in the right direction.     

Binding and textural properties of beef gels processed with κ-carrageenan, egg albumin and microbial transglutaminase

The combined influence of κ-carrageenan (κ-CGN, 0.5%) and egg albumin (EA, 2%) on quality characteristics of beef gels processed without or with 0.5% microbial transglutaminase (MTG) was investigated. Beef gel properties were determined by measuring textural, hydration and colour characteristics. κ-Carrageenan favourably affected hydration properties and thermal stability, yielding lower cooking loss, purge and expressible moisture. It also increased hardness and fracturability of beef gels, but was unable to improve springiness or cohesiveness. Egg albumin either alone or in combination with MTG generally has been found to be inferior to κ-carrageenan for functionality in comminuted meat systems. Addition of EA produced an increase in lightness and yellowness, and a decrease in redness of beef gels, while the presence of κ-carrageenan resulted in lower L(?) and b(?), and higher a(?) values. No significant influence of MTG on gel colour parameters was observed.     

Improving storability,physiological disorders,and antioxidant properties of ‘Bartlett’ and ‘d’Anjou’ pears (Pyrus communis L.) by pre-harvest 1-methylcyclopropene spraying

Ethylene continues to be a major factor influencing quality of European pears during storage. Although research has been done on the effect of pre-harvest 1-methylcyclopropene (1-MCP) on physiological characteristics in pears, a full understanding of cultivar response and antioxidant metabolism remains elusive. Spraying 1-MCP on ‘Bartlett’ and ‘d’Anjou’ pears was studied with respect to physiology, storage and eating quality, disorders, and antioxidant properties at two harvest date (H1 and H2) during storage and ripening. Treatment with 1-MCP extended the harvest window of ‘Bartlett’ and ‘d’Anjou’ pears 3 and 4 days, respectively, without reducing storage or eating quality. Treatment with 1-MCP reduced ethylene production (EPR) and respiration rates (RR), maintained fruit firmness and green colour during storage and retarded development of desirable melting texture in both cultivars. Additionally, 1-MCP lowered the incidence of disorders by alleviating membrane lipid peroxidation, retaining high total flavonoids (TF) and antioxidant capacity, and enhancing superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) activity in both cultivars. Overall, pre-harvest 1-MCP applications could extend storage time of ‘Bartlett’ and ‘d’Anjou’ pears to 5 and 6 months, respectively, at −1.1 ± 0.5 °C, by reducing ethylene synthesis and enhancing antioxidant metabolism.     

Exudate gums: chemistry,properties and food applications – a review

Gums are complex carbohydrate molecules which have the ability to bind water and form gels at low concentration. These carbohydrates are often associated with proteins and minerals in their structure. Gums are of various types such as seed gums, exudate gums, microbial gums, mucilage gums, seaweeds gums, etc. Exudate gums are plant gums which ooze out from bark as a result of a protection mechanism upon injury. Exudate gums have been used by humans since ancient times for various applications due to their easy availability. The main characteristics which make them fit for use in various applications are viscosity, adhesive property, stabilization effect, emulsification action and surface-active property. Major applications of these gums are in food products, the paper, textile, cosmetics and pharmaceutical industries, oil-well drilling, etc. In the present paper, the chemistry, properties, processing and applications of commercially available exudate gums such as acacia gum or gum arabic, karaya gum, ghatti gum and tragacanth gum are discussed. Recent literature reveals that apart from the above mentioned applications, these gums also have nutritional properties which are being explored. Other gums cannot replace them because of their certain unique characteristics. © 2020 Society of Chemical Industry     

Studies on apple and blueberry fruit constituents: do the polyphenols reach the colon after ingestion?

The aim of our studies was to determine the amount of polyphenols reaching the colon after oral intake of apple juice and blueberries. After a polyphenol-free diet healthy ileostomy volunteers consumed a polyphenol-rich cloudy apple juice while others consumed anthocyanin-rich blueberries. Ileostomy effluent was collected and polyphenols were identified using HPLC-DAD as well as HPLC-ESI-MS/MS; quantification was performed with HPLC-DAD. Most of the orally administered apple polyphenols were absorbed from or metabolized in the small intestine. Between 0 and 33% of the oral dose was recovered in the ileostomy bags with a maximum of excretion after 2 h. A higher amount of the blueberry anthocyanins under study (up to 85%, depending on the sugar moiety) were determined in the ileostomy bags and therefore would reach the colon under physiological circumstances. Such structure-related availability has to be considered when polyphenols are used in model systems to study potential preventive effects in colorectal diseases.     

Enhanced utilisation of nonmarketable fish: physical,nutritional and sensory properties of ‘clean label’ fish burgers

Four ‘clean label’ formulations for fish burgers made with mechanically separated fish meat were characterised in sensory, textural and chemical terms. The formulations differed in the ratios of European sea bass to rainbow trout (50:50 and 30:70) and the ratios of fish to potato flakes (dry matter ratio, DMR: 2.5:1 and 1.5:1). The sensory profile was mainly influenced by DMR. Recipes with the higher DMR were positively correlated with sandy, dry and crusty attributes, salty taste and overall flavour. Soft texture was perceived for recipes with the lower DMR, although no differences in texture were detected by a texturometer. Lowering DMR increased ash and water content and decreased protein content, as expected. The results indicated that 100 g of burger provided more essential fatty acids than the recommended daily intake, irrespective of formulation. In conclusion, multiple factor analysis indicated that the main changes detected and perceived were due to DMR.     

High-pressure as a tool to study some proteins’ properties: conformational modification,activity and oligomeric dissociation

Hydrostatic pressure, as temperature, constitutes an efficient physical parameter to modify equilibrium and rate of biological processes. In this review, we will not present all the implications of high-pressure, but we will focus on proteins’ structural conformational modification, unfolding, oligomeric or protein aggregates dissociation and enzymatic activity. To this aim, some optical methods that were used in association with high-pressure to study protein structures (i.e. fourth derivative absorbance spectroscopy, fluorescence spectroscopy, infrared spectroscopy) and protein activities (kinetics measurements: stopped-flow and pressure jump methods) will be described in details. Some applications of these methods will be given including effects on proteins of food interest.     

Effects of different vinification technologies on physico-chemical properties and antioxidant activity of ‘Falanghina’ and ‘Bombino bianco’ wines

The present research was aimed to compare the traditional white vinification with a combined cryomaceration–vinification in reductive conditions, by evaluating their effects on chemical and physical indices and on antioxidant compounds of ‘Falanghina’ and ‘Bombino bianco’, two wine grape cultivars of southern Italy. According to the results, the two cultivars showed similar behaviour in response to the same vinification protocol. The processing conditions mainly affected physico-chemical characteristics such as titratable acidity, pH, SO₂, tartaric and malic acids, phenolic concentrations, and antioxidant activity. Titratable acidity decreased with cryomaceration due to the tartrate precipitation, whereas the malic acid was greatly extracted from pulps and skins. In the reductive conditions applied, the SO₂ was protected by the presence of ascorbic acid; thus, the wines exhibited higher free/total SO₂ ratio. Cryomaceration combined with vinification in reductive conditions allowed a greater extraction of phenolic compounds from skins and, consequently, a greater antioxidant activity compared to the traditional winemaking. This behaviour was due to both the protection exerted by the low temperatures and the solubilisation of proanthocyanidins and flavans reactive with vanillin favoured by the high free SO₂ content.     

Use of β-glucan from spent brewer's yeast as a thickener in skimmed yogurt: Physicochemical,textural, and structural properties related to sensory perception

Powdered β-glucan extracted from brewer's yeast (Yestimun, Leiber GmbH, Bramsche, Germany) was incorporated into skimmed-milk yogurt at varying concentrations (0.2–0.8% wt/wt) to investigate its potential application as a thickener. The effect of β-glucan fortification on the nutritional profile, microstructure, physicochemical properties, and texture of freshly prepared yogurts was investigated. Sensory evaluation was also conducted and was correlated with instrumental analysis. The addition of Yestimun significantly reduced the fermentation time of the yogurt mix from 4 h to 3 h. Scanning electron microscopy revealed that β-glucan particles formed small spherical clusters within the yogurt matrix. The majority of the physicochemical properties (syneresis, viscosity, color, and titratable acidity) remained unaffected by the incorporation of Yestimun in the recipe. Textural properties showed a gradual increment with increasing β-glucan concentration. Hardness, total work done, adhesive force, and adhesiveness increased by 19.27, 23.3, 21.53, and 20.76%, respectively, when using the highest amount of Yestimun powder. Sensory analysis (n = 40) indicated that fortifying yogurt with Yestimun at 0.8% (wt/wt) concentration may affect overall acceptance ratings, which was attributed to adverse flavor and aftertaste effects. However, the overall liking score of the yogurt (5.0/9.0) shows potential for commercialization of the product.     

Enrichment of chips with fibre from a tiger-nut (Cyperus esculentus) milk co-product at ‘source of fibre foods’ and ‘high fibre content foods’ levels: impact on processing,physico-chemical and sensory properties

The impact of integrating a tiger-nut milk co-product into the wheat chip production process for enriching fibre content to meet European recommendations for ‘source of fibre foods’ and ‘high fibre content foods’ was studied. Four different flours, based on their composition and particle size, were obtained from the co-product. Wheat flour was substituted at the 5%, 10% and 20% levels with the co-product, and the processing, physico-chemical and sensory properties of chip were studied. In the baking phase, mass loss was more marked for the substituted samples (42%) than the control (34%), but differences diminished after the tempering time (33%) by absorbing moisture from the environment. This effect was related to the increased chips surface (≈43%) in the forming phase because dough retraction decreased. The co-product as a fibre source produced alterations to chip processing and its physico-chemical properties should be taken into account. However, chips positively impacted consumer acceptability.