Nitration of Tyrosine in the Mucin Glycoprotein of Edible Bird's Nest Changes Its Color from White to Red

Edible Bird's Nest as a Potential Cognitive Enhancer

Cognitive enhancement is defined as the augmentation of the mind's core capabilities through the improvement of internal or external information processing systems. Recently, the focus has shifted to the potential therapeutic effects of natural products in improving cognitive function. Edible bird's nest (EBN) is a natural food substance derived from the saliva of swiftlets. Until today, EBN is regarded as a high-priced nutritious food with therapeutic effects. The effectiveness of dietary EBN supplementation to enhance brain development in mammals has been documented. Although the neuroprotection of EBN has been previously reported, however, the impact of EBN on learning and memory control and its potential as a cognitive enhancer drug remains unknown. Thus, this article aims to address the neuroprotective benefits of EBN and its potential effect as a cognitive enhancer. Notably, the current challenges and the future study direction in EBN have been demonstrated.

Tracking structural changes of protein residues by two-dimensional correlation surface-enhanced Raman spectroscopy

In-situ tracking structural changes of protein residues was developed by two-dimensional correlation surface-enhanced Raman spectroscopy (2DC-SERS). The change order of SERS fingerprints during artificial nitrification of edible bird's nest (EBN) was interpreted as the structural changes of amino acid residues. It inherently realizes reliable recognition of natural EBN and artificially dyed fakes. Both this direct structural tracking of protein residues and the indirect azo dye testing of nitrites/nitrosamines could be used as indicators for discriminating different EBN before and after the artificial dyeing. Limit of detection (LOD) for nitrite and NDMA is about 40.6 ppb and 88.1 ppb, respectively. A conceptual logical circuit of the OR gate was constructed by considering the protein structural indicator (INPUT1) and the nitrite indicator (INPUT2) as two independent inputs for automatic recognition of different EBN samples. A data-driven analog soft independent modeling (DD-SIMCA) model could quickly distinguish normal EBN from A-EBN with 98% specificity.

Edible Bird's Nest: The Functional Values of the Prized Animal-Based Bioproduct From Southeast Asia-A Review

Edible Bird's Nest (EBN) is the most prized health delicacy among the Chinese population in the world. Although some scientific characterization and its bioactivities have been studied and researched, no lights have been shed on its actual composition or mechanism. The aim of this review paper is to address the advances of EBN as a therapeutic animal bioproduct, challenges and future perspectives of research involving EBN. The methodology of this review primarily involved a thorough search from the literature undertaken on Web of Science (WoS) using the keyword "edible bird nest". Other information were obtained from the field/market in Malaysia, one of the largest EBN-producing countries. This article collects and describes the publications related to EBN and its therapeutic with diverse functional values. EBN extracts display anti-aging effects, inhibition of influenza virus infection, alternative traditional medicine in athletes and cancer patients, corneal wound healing effects, stimulation of proliferation of human adipose-derived stem cells, potentiate of mitogenic response, epidermal growth factor-like activities, enhancement of bone strength and dermal thickness, eye care, neuroprotective and antioxidant effects. In-depth literature study based on scientific findings were carried out on EBN and its properties. More importantly, the future direction of EBN in research and development as health-promoting ingredients in food and the potential treatment of certain diseases have been outlined.

Potential Residual Contaminants in Edible Bird's Nest

Edible bird’s nest (EBN) is recognized as a nourishing food among Chinese people. The efficacy of EBN was stated in the records of traditional Chinese medicine and its activities have been reported in many researches. Malaysia is the second largest exporter of EBNs in the world, after Indonesia. For many years, EBN trade to China was not regulated until August 2011, when a safety alert was triggered for the consumption of EBNs. China banned the import of EBNs from Malaysia and Indonesia due to high level of nitrite. Since then, the Malaysia government has formulated Malaysia Standards for swiftlet farming (MS 2273:2012), edible bird’s nest processing plant design and management (MS 2333:2010), and edible bird’s nest product quality (MS 2334:2011) to enable the industry to meet the specified standards for the export to China. On the other hand, Indonesia's EBN industry formulated a standard operating procedure (SOP) for exportation to China. Both countries can export EBNs to China by complying with the standards and SOPs. EBN contaminants may include but not limited to nitrite, heavy metals, excessive minerals, fungi, bacteria, and mites. The possible source of contaminants may come from the swiftlet farms and the swiftlets or introduced during processing, storage, and transportation of EBNs, or adulterants. Swiftlet house design and management, and EBN processing affect the bird’s nest color. Degradation of its optical quality has an impact on the selling price, and color changes are tied together with nitrite level. In this review, the current and future prospects of EBNs in Malaysia and Indonesia in terms of their quality, and the research on the contaminants and their effects on EBN color changes are discussed.

Identification of blood-red color formation in edible bird's nests provides a new strategy for safety control

In order to reveal the color formation mechanism of blood-red edible bird's nests (EBNs) and develop a quick and specific strategy to distinguish the artificial fake one, multiple methods of UPLC-TOF/MS, UV, NMR, FT-IR and 2D IR were used to detect the chemical markers of the reddening reaction, the results showed that the reddening substances were C₉H₁₀N₂O₅ and C₉H₉NO₆, which were verified as products of a phenol-keto tautomerism evolved from l-tyrosine. Moreover, natural and artificial red EBNs with varying degrees of chemical fumigation also can be successfully distinguished using the chemical markers, and the protein variation in SDS-PAGE gel could also support the distinction. This work established a systematic method of chemical identification for both natural and artificial blood-red EBNs, and provided a new identification strategy for food safety control that can promote the development of a healthier market of EBNs.

A comprehensive review of edible bird's nest

Edible bird's nest (EBN) is built by seven species of Aerodramus and Collocalia (Apodidae), using salivary gland secretion mixed with feathers or grass during the breeding. Its rich nutritional values such as anti-aging activity, immunomodulatory and antioxidant activity make consumers flock to it. Consumers' pursuit, on the one hand, aroused the arrogance of counterfeiters, which eventually leads to food safety problems. On the other hand, it promotes the in-depth studies of EBN in all aspects, such as compositions, biological activities, authenticity identification, quality control, and so on. This paper presented the origins and classifications of EBN and the current situation of EBN industry in detail; reviewed the nutritional compositions, pharmacological actions, identification, inspection and content determination of EBN comprehensively; and prospected the future research directions to provide suggestions for the further study.

Calcite Deposits Differentiate Cave from House-Farmed Edible Bird's Nest as shown by SEM-EDX, ATR-FTIR and Raman Microspectroscopy

The difference between the swiftlet white edible bird's nest from limestone caves versus house-farmed ones, especially in response to high temperature and stewing time in water where the latter type would disintegrate readily, has been a puzzle for a long time. We show that edible bird's nests from the limestone caves have calcite deposits on the surface of the nest cement as compared to the house-farmed nests which are built by swiftlets on timber planks. The micron and sub-micron calcite particles are seen in SEM-EDX and further characterized by ATR-FTIR and Raman microspectroscopy. The calcite deposits make it possible for the cave nest to retain a gelatinous texture under the harsh retort conditions at 121 °C for 20 mins in commercial bottling. We show that house-farmed nests can be soaked in CaCl₂ (aq) followed by rinsing with Na₂ CO₃ (aq) to grow the same calcite deposits on the nest cement with the same characteristic as cave nests. Therefore, there should no longer be a need to harvest cave nests, and we can better conserve the dwindling population and natural habitats of cave swiftlets.

Complete digestion of edible bird's nest releases free N-acetylneuraminic acid and small peptides: an efficient method to improve functional properties

Edible bird's nest (EBN), an Asian health food, contains insoluble proteins and conjugated N-acetylneuraminic acid (NANA) that are difficult to be absorbed by humans. In order to increase the nutritional value of EBN, we developed methods to digest EBN targeting the release of proteins and NANA. By using simulated gastric fluid under acidic conditions, the complex proteins were fully digested into smaller peptides, and in parallel, NANA was fully released from the conjugated form. The completely digested EBN showed better nutraceutical properties. In a skin whitening test, the EBN digest showed stronger inhibition of melanogenesis of cultured B16 cells and enzymatic activity of tyrosinase, as compared to that of undigested EBN. In addition, the EBN digest exhibited stronger osteogenic activity in cultured osteoblasts. Thus, the complete digestion of EBN could be applied to the development of a new generation of EBN health food products, including EBN drinks and skincare products.