Water vapor and oxygen permeability of wax films

The water vapor (WVP) and oxygen (O₂P) permeabilities of beeswax (BW), candelilla wax (CnW), carnauba wax (CrW) and microcrystalline wax (MW), formed as freestanding films, were determined. CnW and CrW both had small values for O₂P (0.29 and 0.26 g·m⁻¹·sec⁻¹·Pa⁻¹ × 10⁻¹⁴, respectively), which are less than half the value for high-density polyethylene and about a decade greater than the value for polyethylene terephthalate. O₂P values for BW and MW were about 6−9× greater than those of CnW and CrW. WVP of CnW was 0.18 g·m⁻¹·sec⁻¹·Pa⁻¹ × 10⁻¹², which is about one-half the value for CrW and MW and about one-third the value for BW. The WVP of CnW was somewhat less than that of polypropylene and somewhat greater than that of high-density polyethylene. Differences in permeabilities among the wax films are attributed mainly to differences in chemical composition and crystal type as determined by X-ray diffraction.     

Detection of beeswax adulterations using concentration guide‐values

The concentrations of 102 chemical compounds (saturated and unsaturated hydrocarbons, palmitates, total and free acids, total hydroxyacids, total and free alcohols, acidic monoesters and monoesterified 1,2,3‐propanetriols) have been determined by GC/FID on white and yellow comb beeswax of Apis mellifera from different regions of Spain. Guide‐value ranges are proposed for its characterization and to discriminate adulterated foundation beeswax sheets. The concentrations of many compounds resulted to be statistically different for white and yellow beeswaxes, while the observation of concentrations out of normal in some marketed foundation beeswax sheets suggested their adulteration. However, the measurement of anomalous concentrations in foundation beeswax sheets did not imply necessarily their rejection by the bees.     

Influence of Storage on Physicochemical and Volatile Features of Enriched and Aromatized Wax Organogels

In this study, virgin olive oil (VOO) organogels were produced with beeswax (BW) and sunflower wax (SW) and enriched with β‐carotene, vitamin D₃ and E as well as aromatized with strawberry, banana, and butter aromas. The physicochemical, thermal, structural, and sensorial properties of the fresh organogel samples were determined. The peroxide values, antioxidant activities, firmness, and volatile compositions of the fresh samples and those stored for 3 months were also determined. The organogels were not only stable, uniform, and homogenous during the storage period but also the added components did not affect the organogel properties. The panel defined three appearance, four texture, three mouthfeel, four aroma, and four flavor terms to describe the organogels sensorially. Moreover, the added aroma (banana, strawberry, and diacetyl‐butter) components of the fresh and stored organogels were quantified by GC/MS‐SPME. In conclusion, these results demonstrated that beeswax and sunflower wax are very suitable to preserve the aromatic characteristics of these types of spreadable products.     

B-HIVE: Beeswax hydrogen isotopes as validation of environment. Part I: Bulk honey and honeycomb stable isotope analysis

Stable isotope analysis is an established method for detecting honey adulteration. We extend its application to include honey and honeycomb region-of-origin assignment using hydrogen (δ²H) and oxygen (δ¹⁸O) isotopes. We observed that liquid honey δ²H and δ¹⁸O values had the potential to change because of water absorption and H atom exchange between sugars and water vapour. This suggested that liquid honey has limited use for geo-location, because specimens will record analysis location humidity. Paired liquid honey and honeycomb δ²H values were significantly correlated; therefore, we propose using wax δ²H values for region-of-origin assignment. We observed significant correlations between beeswax δ²H values and both mean annual precipitation and tap water δ²H values predicted for hive locations, suggesting that geographical variation in water δ²H values are recorded by beeswax δ²H values. This survey demonstrates the promise of stable isotopes for region-of-origin assignment, using honeycomb wax δ²H values, which complements carbon isotope analysis to detect adulteration.     

蜂蜡净油挥发性成分的分析和研究

采用气相色谱 质谱联用技术 ,通过质谱库检索并结合保留指数 ,对蜂蜡净油的挥发性成分进行了定性分析 ;同时采用气相色谱技术 ,对其中的大部分挥发性成分进行了定量分析。共检出 75个组分。主要成分为 :1,8 桉树脑 (1.70 % )、芳樟醇 (6 .5 3% )、乙酸芳樟酯 (12 .5 1% )、乙酸松油酯 (1.85 % )、苯乙酸甲酯 (2 .5 9% )、苯乙酸乙酯 (2 .6 0 % )、苯甲醇 (5 .6 7% )、丁酸苯乙酯 (2 .11% )、洋茉莉醛 (1.0 5 % )、苯乙酸 (14 .79% )、香兰素 (8.0 1% )、苯乙酸苄酯 (10 .97% )、肉桂酸苄酯 (2 .5 5 % )等。     

蜂蜡中掺杂物的测定

蜂蜡较贵,而市场上出售的蜂蜡又常被加入一些掺杂物,这些掺杂物会极大地影响蜂蜡用户的最终产品的质量。通过样品外观的观察初步定性是否掺有杂质;利用纯蜂蜡在苯中溶解,而掺入的石膏、面粉和淀粉等杂质在苯中不溶而定量鉴定这类杂质;由酸值变化和乙醇溶解物的量,测定掺入的硬脂酸等酸性物质或其它的非酸性物质;由皂化值变化,定量测定掺入的动物脂等酯类物质或其它的非酯类物质;根据蜂蜡中的烃类在浓硫酸中可被炭化,加入的石蜡等矿物蜡不被炭化来测定此类掺杂物。由此初步建立了一个蜂蜡中多种掺杂物同时存在时各掺杂物的种类和含量测定的分析体系。所用仪器简单,宜于推广应用     

Effect of native and acetylated‐crosslinked waxy corn starch‐beeswax coatings on quality attributes of raspberries during storage

Edible coatings (ECs) are a thin layer of a mixture of edible materials, applied in the liquid state and dried over the surface of a food product to maintain its quality during storage. This work was aimed to study the effect of ECs made from wx corn starch (WCS) or acetylated cross‐linked starch (ACLS) added with beeswax on fresh raspberry quality attributes during short‐term cold storage. Freshly harvested fruits were coated, dried, packed in plastic trays and stored up to 8 days at 4°C. During storage quality parameters such as firmness, respiration rate, anthocyanins content, total phenols, color changes, and weight loss were evaluated. A clear effect on control of respiration rate was observed in coated raspberries. Respiration rate of uncoated fruit was 4.5 ± 0.28 mmol/kg/h and decreased to 4.2 ± 0.27 for ACLS and to 4.1 ± 0.08 mmol/kg/h for WCS‐coated raspberries, after 56 h of storage at 15°C. Ethylene production followed a similar trend under these conditions decreasing from 0.043 ± 0.005 to 0.034 ± 0.004 mmol/kg/h for uncoated and ACLS coated fruits, respectively, indicating an effect on ripening control. Additionally, ACLS and WCS coatings permitted the preservation of color without affecting anthocyanins content. However, the presence of anaerobic metabolites and reduction of terpenes production in cold stored coated raspberries indicated hypoxic conditions, which can adversely affect shelf‐life quality attributes of raspberries such as firmness and weight loss.     

Effect of freezing on physical properties of whey protein emulsion films

The objective of this work was to study the effect of the freezing process on physical properties of whey protein emulsion films with different beeswax content dried at 5 °C. Thickness, microstructure, water vapour permeability, solubility in water, sorption isotherms and mechanical properties were measured in Control and Frozen films. The freezing process did not cause fractures or perforations in films, but films with beeswax showed a change in the appearance of the lipids after freezing. Only films with 40% of beeswax showed a significant increase in the water vapour permeability after freezing. The freezing process did not affect film solubility in water but produced small differences in the equilibrium moisture content values. In the puncture test, the freezing process increased puncture strength and deformation of films without beeswax but those parameters were not affected in films with beeswax. In tensile test, tensile strength and elastic modulus decreased, but elongation was not affected by freezing process. Principal component analysis accomplished an adequate condensation of the date grouping samples according to film formulation and treatment (Control and Frozen films). Indeed, the relationships of sample grouping and measured parameters were enlightened by principal component analysis. In conclusion, whey protein emulsion films were resistant to the freezing process (freezing, frozen storage and thawing) and could be a good alternative as a treatment to preserve the quality of frozen foods.     

The effects of the addition of corn husk fibre,kaolin and beeswax on cross-linked corn starch foam

Significant efforts have recently been made to improve the physical properties of starch foams formed using baking processes. For example, cross-linking starch with 0.126 g/kg glyoxal considerably reduces the baking time, density and water absorption of starch foams. In this study, we attempted to further develop the physical properties of glyoxal cross-linked starch foam by adding corn husk fibre, kaolin, beeswax and combinations of these products. We also studied the effects of these components on the microstructure and physicochemical and mechanical properties of trays. Starch-based trays in which additives were used showed improved water resistance. The water absorption capacities of the trays were 13%, 14% and 9% when combinations of kaolin/beeswax, fibre/beeswax and fibre/kaolin/beeswax were added, respectively.