Coconut milk treated by atmospheric cold plasma: Effect on quality and stability

The role of fat content in coconut milk: Stability and digestive properties

The fat in coconut milk contributes to unique flavour, while increasing fat content affects stability of the coconut milk. In this study, coconut water and fat were separated, recombined, and homogenized to obtain coconut milk with different fat contents (0-20 %). Emulsifying properties, stability, and digestibility of coconut milk with different fat contents were comprehensively evaluated. The results showed that as the fat content increased from 0 to 20 %, the droplet size increased from 2.18 to 4.70 μm and the viscosity showed an increasing trend. During storage and freeze-thaw, coconut milk with 5 % and 10 % fat content showed excellent stability. In addition, coconut milk with 10 % fat content had superior fat digestibility, which was related to high affinity of pancrelipase. In short, this study revealed that fat content below 10 % can withstand environmental factors such as storage, lipid oxidation, and freeze-thaw, which can be accurately developed as coconut milk products.

Structural characteristics and stability analysis of coconut oil body and its application for loading β-carotene

In this work, we investigated structural characteristics and stability analysis of the coconut oil body (COB) and its application for loading β-carotene (β-CA). The COB contained neutral lipids (81.1 ± 2.1 %), membrane proteins (0.6 ± 0.0 %), and moistures (18.3 ± 3.2 %), in which the molecular weights of membrane proteins ranged from 12 kDa to 40 kDa, as analyzed by the SDS-PAGE. The COB exhibited a small droplet diameter (5.1 ± 0.3 µm) with a monomodal diameter distribution, as reflected by the dynamic light scattering. The COB showed stable states at alkaline pH values (pH 8-10) and instability against ionic strengths (50-200 mmol/L) and thermal treatment (30-90℃) after analyzing the instability indexes. COB-based emulsions were favorable for the loading and retention of β-CA, as reflected by free fatty acids release rates and bioaccessibility in the simulated gastrointestinal digestion. This study will contribute to using the coconut oil bodies for loading bioactive nutraceuticals to enhance their bioaccessibility.

Chemical and physical changes induced by cold plasma treatment of foods: A critical review

Cold plasma treatment is an innovative technology in the food processing and preservation sectors. It is primarily employed to deactivate microorganisms and enzymes without heat and chemical additives; hence, it is often termed a "clean and green" technology. However, food quality and safety challenges may arise during cold plasma processing due to potential chemical interactions between the plasma reactive species and food components. This review aims to consolidate and discuss data on the impact of cold plasma on the chemical constituents and physical and functional properties of major food products, including dairy, meat, nuts, fruits, vegetables, and grains. We emphasize how cold plasma induces chemical modification of key food components, such as water, proteins, lipids, carbohydrates, vitamins, polyphenols, and volatile organic compounds. Additionally, we discuss changes in color, pH, and organoleptic properties induced by cold plasma treatment and their correlation with chemical modification. Current studies demonstrate that reactive oxygen and nitrogen species in cold plasma oxidize proteins, lipids, and bioactive compounds upon direct contact with the food matrix. Reductions in nutrients and bioactive compounds, including polyunsaturated fatty acids, sugars, polyphenols, and vitamins, have been observed in dairy products, vegetables, fruits, and beverages following cold plasma treatment. Furthermore, structural alterations and the generation of volatile and non-volatile oxidation products were observed, impacting the color, flavor, and texture of food products. However, the effects on dry foods, such as seeds and nuts, are comparatively less pronounced. Overall, this review highlights the drawbacks, challenges, and opportunities associated with cold plasma treatment in food processing.

Mechanism for improving the in vitro digestive properties of coconut milk by modifying the structure and properties of coconut proteins with monosodium glutamate

In this paper, the effect of monosodium glutamate (MSG) on coconut protein (CP) solubility, surface hydrophobicity, emulsification activity, ultraviolet spectroscopy and fluorescence spectroscopy was investigated. Meanwhile, the changes in the in vitro digestive properties of coconut milk were also further analyzed. MSG treatment altered the solubility and surface hydrophobicity of CP, thereby improving protein digestibility. Molecular docking showed that CP bound to pepsin and trypsin mainly through hydrogen bonds and salt bridges. And MSG increased the cleavable sites of pepsin and trypsin on CP, thus further improving the protein digestibility. In addition, MSG increased the Na+ concentration in coconut milk, promoted flocculation and aggregation between coconut milk droplets, which prevented the binding of lipase and oil droplets and inhibited lipid digestion. These findings may provide new ideas and insights to improve the digestive properties of plant-based milk.

Interaction between liposome and myofibrillar protein in surimi: Effect on gel structure and digestive characteristics

This study investigated the effects of the interaction between liposomes and myofibrillar protein (MP) on tilapia surimi. The strong interaction between liposomes and MP was primarily mediated through hydrogen bonding and hydrophobic interaction. Liposomes caused the unfolding of MP structure, resulting in the decrease of α-helix content and transformation of spatial structure. Notably, the appropriate ratio of liposomes improved the gel properties of tilapia surimi. The water distribution, microstructure, and texture characteristics further confirmed that liposomes strengthened the structure of surimi gel through non-covalent bonds. However, excessive liposomes (1.0 %) weakened gel characteristics and texture. Moreover, the proper ratio of liposomes enhanced the stability of surimi gels during digestion, reducing protein digestibility from 66.0 % to 54.8 %. Curcumin-loaded liposomes in gel matrix notably delayed digestion and improved bioavailability. This delay in digestion was attributed to the ability of liposomes to decrease the interaction between MP and digestive enzymes. This study provides new insight into the application of liposomes in protein-rich food matrixes.

Improvement of emulsifying stability of coconut globulin by noncovalent interactions with coffee polyphenols

Coconut milk is an unstable emulsion system, mainly stabilized by proteins, which limits the development of the food industry. The aim of this study was to investigate mechanisms for increasing emulsion stability through the interaction between coffee polyphenols (CPs) and coconut globulin (CG), the main protein in coconut milk. Caffeic acid (CA), chlorogenic acid (CHA), and ferulic acid (FA) were selected as CP models. The results showed that hydrogen bond interactions mainly occurred between CG and CPs (CG-FA < CG-CA < CG-CHA). CHA containing quinic acid preferentially formed a strong interaction with CG. The interaction changed the lipophilicity of CG and facilitated the formation of a dense and thick interfacial film at the oil-water interface. Furthermore, the emulsion stabilized by CG-CPs showed excellent stability after storage, centrifugation, pH, and salt treatment, especially CG-CHA. This study could provide a theoretical basis for improving the stability of coconut milk products.