Yanyun Zhao’s research while affiliated with Oregon State University and other places

Spent coffee grounds (SCG) are the waste byproducts of coffee brewing. While SCG can be valorized to produce functional biopolymers due to their valuable structural components, the lignocellulosic structure of SCG is resistant to degradation because of the tightly bound lignin. Therefore, a pretreatment step is required before pulping with peracetic acid (PAA), an eco‐friendlier alternative to traditional pulping methods, to facilitate the extraction of these desired cellulosic materials. Formic acid:acetic acid:deionized water (FA:AA:W = 30:50:20) or 60% (v/v) ethanol pretreatments were applied to SCG to compare the characteristics of the resulting cellulosic materials after PAA pulping. Lignocellulose analysis showed that the lignin content (7.06%) of ethanol pretreated SCG was significantly lower (p < 0.05), and the cellulose content (29.52%) was significantly higher (p < 0.05) than the untreated SCG (15.50% and 11.50%, respectively), indicating that an adequate amount of lignin was removed to obtain the cellulosic materials after the pretreatment process. Morphological and structural changes in the lignin and hemicellulose were observed in all the pretreated SCG, which further confirmed that these components were degraded with pretreatments and pulping. Ethanol pretreated SCG showed the most optimal results based on the greatest lignin decrease seen from its lignocellulose composition, appearance, and structure. This study exemplified a conversion process to extract cellulosic materials from SCG more efficiently to utilize for cellulose‐based products and verify its potential to be valorized as a waste byproduct. Practical Application Coffee companies can provide the spent coffee grounds (SCG) they produce to develop cellulose‐based materials to make biodegradable packaging products rather than throwing them out or burning them. Using SCG for producing cellulose‐based materials can help promote sustainability and reduce food waste worldwide. SCG can be utilized as an alternative source based on their abundance and desired biopolymeric properties, providing innovative solutions to industries and increasing consumer awareness of this cause.

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.

The separation sheets for fruit leather are traditionally made of plastic film or wax paper, which not only leads to environmental issues but also is inconvenience to consumers. This study evaluated edible fruit leather separation sheets using food polymers, including hydroxypropyl methyl cellulose (HPMC) and incorporation of cranberry pomace water extract (CPE) for providing natural fruit pigment, flavor, and phenolics. HPMCCPE film was then further improved by incorporating hydrophobic compound (oleic acid, OA) and vitamin E (VE) via cellulose nanocrystal (CNC) Pickering emulsion (CNCP) for enhancing film hydrophobicity and nutritional benefit, respectively. The CNCP–HPMCCPE film exhibited reduced water vapor permeability (∼0.033 g mm/m² d Pa) compared to HPMCCPE film (∼0.59 g mm/m² d Pa) and had the least change in mass and moisture content when wrapping fruit leather for up to 2 weeks of ambient storage. The fruit leather wrapped by CNCP–HPMCCPE film showed lower weight change than those by films without CNCP due to low mass transfer between film and fruit leather. CNCP resulted in controlled release of VE into a food simulating solvent (ethanol). The developed colorful and edible fruit leather separation sheet satisfied the increased market demands on sustainable food packaging. Practical Application Colorful and flavorful edible films made of edible polymers, fruit pomace water extract, and emulsified hydrophobic compounds with vitamin E were created. The films have the satisfactory performance to replace the conventional fruit leather separation sheet made of plastic or wax paper. The edible films can be eaten with packaged fruit leather for not only reducing packaging waste but also providing convenience and nutritional benefit to consumers. These functional edible films may also be utilized to package other food products for promoting packaging sustainability and nutritional benefit.

Excessive use of single‐use plastic packaging presents an imminent threat to the environment. One of the emerging solutions is using edible food packaging. However, there is lack of consumer information toward edible packaging. This study evaluated consumer attitude, acceptability, and purchase intent of three types of edible food packaging: muffin liner, cranberry pomace fruit leather wrap, and powdered drink sachet. One hundred consumers who frequently consumed muffins, strawberry fruit leather, and powdered lemonade were selected from metropolitan area of Portland, Oregon to participate in the study. The panelists were presented with the edible films and the food products with the edible packaging, information card highlighting the environmental‐friendly edible package, and were prompted with describing the sensory attributes, purchase intent, and qualities regarding the edible packaging with and without food. Overall, panelists liked the three foods with the edible packaging giving overall liking scores of 7.48, 8.06, and 7.48 for the muffin liners, edible fruit leather wraps, and powdered drink sachets, respectively, based on a 9‐point hedonic scale where 1 = dislike extremely and 9 = like extremely. When asked about hypothetical purchase intent, 64%–68% of panelists positively reacted to purchase intent and would buy all three types of edible packaging products. Based on the positive reaction from panelists, edible packaging maybe a possible solution to reducing single‐use plastic packaging in the food industry. This study can be the catalyst for further investigation of the efficacy of different applications of edible food packaging as well as consumer perceptions of eating their packaging. Practical Application Edible food packaging is an emerging solution for reducing single‐use plastic waste. This study investigated consumer attitude, acceptability, and purchase intent of edible food packaging for three food packaging applications, including edible muffin liner, fruit leather wrap, and powdered drink sachet. This study demonstrated that consumers strongly agree that edible packaging would serve as an environmentally sustainable solution to single‐use plastics, and are willing to spend more to purchase these sustainable alternatives. This study provides new information toward the future development of edible packaging and consumer perceptions of eating their packaging.

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.