Chieh‐Yi Lin

Thermal processing of whole fruits often leads to significant quality degradation, limiting consumer acceptance and market value. This study assessed the quality and microbial safety of thermally processed whole blueberries treated with a novel copigmentation and cellulose nanofiber (CNF)‐based layer‐by‐layer (LBL) emulsion coating. It also evaluated sensory attributes and consumer acceptance of three blueberry products made with coated and uncoated (control) blueberries. The coating effectively reduced anthocyanin leaching and preserved the firmness of blueberries after canning. A microbial challenge study confirmed no growth of total aerobic microbial count in inoculated E. coli ATCC 25922 surrogate fruit after thermal processing. In consumer panels ( n = 107), participants rated appearance, color, aroma, texture, and overall liking of three products, such as mixed fruit cup, blueberry fruit cup, and blueberry yogurt, using a 9‐point scale. Control samples generally received higher scores across attributes, with significant differences in overall liking, appearance, color, aroma, and texture. A Just‐About‐Right (JAR) analysis indicated that while the coating enhanced color and aroma, over 35% of participants found the skin “too thick,” and over 40% rated the firmness as “too firm.” The coating was positively received for color in fruit cups and yogurt but deemed too thick and light in mixed fruit cups, suggesting that product‐specific factors influence perception. Future research should focus on refining the coating to better meet consumer expectations for appearance and texture.

This study investigated an ecofriendly peracetic acid delignification process to extract holocellulose from various fiber rich plant‐based byproducts (coconut palm spathe/leaf, apple pulp, wine grape pomace, hazelnut shell, and hemp fiber/hurd), and evaluated their physicochemical, morphological, and thermophysical properties in comparison with commercial cellulose nanofibers produced from wood. Holocellulose from coconut palm spathe has long fiber (~846.7 μm), whereas that from wine grape pomace and hazelnut shell exhibits a cylinder shape of particles with short fiber length (~123.8 and ~ 71.1 μm, respectively). Biofilms cast from apple pulp and hemp fiber holocellulose have higher degradation temperature (361 and 358°C, respectively) than biofilms from other materials, thus more thermally stable. All biofilms demonstrate high UV absorbance, and the biofilm cast from apple pulp holocellulose is transparent with smooth surface. Fourier‐transform infrared spectroscopy analysis confirms the presence of cellulose and hemicellulose as the main components in the biofilms, along with traces of residual lignin that remained after the extraction process. This study demonstrates that holocellulose with varied cellulose morphology and polymeric characteristics could be extracted depending on the type of byproducts and be employed to produce sustainable packaging materials.

Summary: The combined copigmentation and layer‐by‐layer (LBL) hydrophobic coating technique was developed to preserve anthocyanins in thermally processed (TP) whole blueberry fruit in our previous study. This study investigated the impact of the developed technique on the cell wall composition and structure, anthocyanin stability and fruit firmness in non‐thermally (high hydrostatic pressure (HHP)) processed whole blueberry fruit during the refrigerated storage at 4 °C ~ 7 °C. Meanwhile, the wet‐milling process was utilised to treat cellulose nanofiber (CNF) based first layer coating for enhancing adhesion and improving the appearance of LBL coating on the fruit. The developed anthocyanin preservation technique retained significantly (P < 0.05) higher chelator‐soluble pectin in both thermally and HHP processed fruit (102.8 ± 7.0 and 100.8 ± 5.1 mg g⁻¹ dry fruit skin, respectively). The technique also enhanced fruit anthocyanin stability reflected by the bathochromic and hyperchromic effect on fruit skin extract. In addition, it significantly (P < 0.05) enhanced the firmness of HHP (551.2 ± 80.7 g) or TP (579.8 ± 90.9 g) processed fruit during the refrigerated or ambient storage compared with control (488.9 ± 75.8 g). The wet‐milling process was able to fibrillate aggregated cellulosic fibres in the coating suspension, thus improved the adhesion and appearance of LBL coating onto the fruit surface. This study demonstrated that the combined copigmentation and LBL coating, along with wet milling treatment of CNF‐based coating, can effectively preserve anthocyanins in HHP processed whole blueberry fruit during extended refrigeration storage owning to the modification of fruit surface cell wall composition and structure.

To enhance hydrophobicity and surface adhesion of edible coatings onto blueberries, an emulsion system consisting of polysaccharides and oleic acid (OA) was developed and incorporated into layer‐by‐layer (LBL) cellulose nanofiber (CNF)‐based coating. The surface tension (ST) of CNF‐based emulsion coating with chitosan (CS), carboxymethyl cellulose (CMC) and OA was 34.28 mN/m, within the range of critical ST (28.41–37.52 dyne/cm) of blueberry surface after washing and copigmentation treatment by phenolic acid, which is essential to ensure good adhesion of coatings on fruit surface. CNF‐based emulsion coating demonstrated lower water sorption (9.47%) and water solubility (35.42%) and higher water contact angle (82.49 °) than CNF‐based coating without emulsion (control; 378.60%, 51.72%, and 67.37 °, respectively). CNF‐based emulsion coating also showed lower tensile strength (5.9 MPa) and elongation at break (2.55%) than control (28.17 MPa and 17.85%, respectively). CNF‐based emulsion coating was validated on thermally processed blueberries for preventing anthocyanin pigment leaching as the first layer in a LBL coating system with sodium alginate as the second layer. The CNF emulsion incorporated LBL coating system significantly preserved anthocyanin pigment in the processed blueberries compared with that of control due to increased surface adhesion and hydrophobicity and decreased mechanical damage. This study demonstrated the effectiveness of emulsion system in coatings for enhancing hydrophobicity and surface adhesion of coatings to preserve the nutritional and organoleptic qualities of thermally processed blueberries.Practical Application: Degradation of anthocyanins in processed fruit and fruit products has been a long‐term challenge for processed food industry. The hydrophobic and heat‐resistant coatings developed in this study can be used to preserve antioxidant anthocyanin pigments within fruit when subjected to thermal (simulated canning) process in aqueous solution, thus overcoming the barriers that the food industry has been facing. CNF plays a critical role to enhance thermal stability and adhesion of coatings onto fruit surface. The developed technology can be utilized for not only improving existing products, but also developing new and novel fruit products.

This study investigated calcium sulfate and chitosan on the textural modification and microstructure of tofu made from lentils. The addition of varying amounts of calcium sulfate (0–12 mM) and chitosan (0–1.0%) into lentil milk could affect the gel properties of lentil-based tofu. The gel properties, including the hardness and cohesiveness, of lentil-based tofu significantly increased with the addition of 12 mM calcium sulfate, exhibiting a slightly discontinuous network structure and a slightly regular pore network. However, the gel properties including hardness and cohesiveness significantly decreased with the addition of 1.0% chitosan, presenting a slightly continuous network structure with pores. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed that the aggregation of the vicilin, legumin acidic unit and legumin basic unit proteins in lentil milk was induced both by 12 mM calcium sulfate and 1.0% chitosan. Our results suggested that calcium sulfate and chitosan could affect the gel properties, such as hardness and cohesiveness, of lentil-based tofu. Therefore, calcium sulfate and chitosan can be used as practical food additives for the development of texture-modified lentil-based tofu.

Anthocyanins in processed fruit degrade significantly due to their heat and oxygen sensitivity and water solubility. Copigmentation for stabilizing anthocyanins is less effective for whole fruit due to anthocyanins’ location within cell vacuoles surrounded by the epicarp layer as barrier to prevent copigment complexing with anthocyanins. This study investigated strategies for enhancing anthocyanin–phenolic copigmentation on blueberry surface, and integrated copigmentation with layer‐by‐layer (LBL) coating to retain anthocyanin stability in thermally processed blueberries. Results indicated that epicarp layer treatment of fruit by Tween 80 (T80) and CaCl ₂ is important for enhancing anthocyanin–phenolic copigmentation. The sequential copigmentation treatment using T80, ferulic acid, and CaCl ₂ (T80→FA→CaCl ₂ ) or T80, tannic acid, and CaCl ₂ (T80→TA→CaCl ₂ ) resulted in higher ( p < 0.05) retention of total monomeric anthocyanin (3.18 mg/g and 3.38 mg/g, respectively) in thermally processed blueberries after 7‐day ambient storage than that of untreated fruit (2.79 mg/g). Percent polymeric color (PPC) of blueberries treated by T80→FA→CaCl ₂ (15.5%) or T80→TA→CaCl ₂ (17.4%) was lower ( p < 0.05) than that treated by TA alone (22.5%). The LBL coating enhanced microstructure stability for preserving anthocyanins in thermally processed blueberries. This study demonstrated the effectiveness of sequential copigmentation of blueberries after epicarp layer treatment followed by LBL coating for enhancing anthocyanin stability in processed whole fruit. Practical Application: When anthocyanin‐rich fruit is thermally processed, anthocyanins degrade and leach to aqueous packing solution because of its heat sensitivity and water solubility. This study developed an innovative technology through implementing sequential treatments of copigmentation and water‐ and heat‐resistant coating for preventing heat and water degradation of anthocyanins in whole fruit during processing in aqueous media. The developed technology can be practically applied to enhance the quality and health benefits of thermally processed anthocyanin‐rich whole fruit. The technology can not only be utilized to improve existing fruit products, but also develop new and novel fruit products.