Collagen-chitosan-hydroxyapatite composite scaffolds for bone repair in ovariectomized rats.

Lesions with bone loss may require autologous grafts, which are considered the gold standard; however, natural or synthetic biomaterials are alternatives that can be used in clinical situations that require support for bone neoformation. Collagen and hydroxyapatite have been used for bone repair based on the concept of biomimetics, which can be combined with chitosan, forming a scaffold for cell adhesion and growth. However, osteoporosis caused by gonadal hormone deficiency can thus compromise the expected results of the osseointegration of scaffolds. The aim of this study was to investigate the osteoregenerative capacity of collagen (Co)/chitosan (Ch)/hydroxyapatite (Ha) scaffolds in rats with hormone deficiency caused by experimental bilateral ovariectomy. Forty-two rats were divided into non-ovariectomized (NO) and ovariectomized (O) groups, divided into three subgroups: control (empty defect) and two subgroups receiving collagen/chitosan/hydroxyapatite scaffolds prepared using different methods of hydroxyapatite incorporation, in situ (CoChHa1) and ex situ (CoChHa2). The defect areas were submitted to macroscopic, radiological, and histomorphometric analysis. No inflammatory processes were found in the tibial defect area that would indicate immune rejection of the scaffolds, thus confirming the biocompatibility of the biomaterials. Bone formation starting from the margins of the bone defect were observed in all rats, with a greater volume in the NO groups, particularly the group receiving CoChHa2. Less bone formation was found in the O subgroups when compared to the NO. In conclusion, collagen/chitosan/hydroxyapatite scaffolds stimulate bone growth in vivo but abnormal conditions of bone fragility caused by gonadal hormone deficiency may have delayed the bone repair process.

Recent advances in the development of smart, active, and bioactive biodegradable biopolymer-based films containing betalains.

Betalains are natural nitrogenous water-soluble pigments found in species belonging to the Caryophyllales order and in mushrooms. Betalains can be considered multifunctional molecules due to their diverse bioactivities such as antioxidant, antimicrobial, anticancer, and anti-inflammatory. Furthermore, they can detect pH variations in foods and are considered promising colorimetric bioindicators. The bioactivities of betalains have improved their use as active and bioactive agents, and colorimetric indicators in the development of edible and biodegradable films for foods, which are trends in the food packaging market. Thus, this review presents the state-of-art information on the use of betalains as a multifunctional molecule in the development of smart, active, and bioactive edible and biodegradable packaging for foods. Studies have revealed that betalains can be successfully used to develop: smart films to indicate the freshness and spoilage of foods such as shrimp, fish, and chicken; active films with antimicrobial and antioxidant potentials to increase the shelf life of sausage and shrimp; and bioactive films with health benefits.

Bio-nanocomposite edible coatings based on arrowroot starch/cellulose nanocrystals/carnauba wax nanoemulsion containing essential oils to preserve quality and improve shelf life of strawberry.

This study investigated the effects of bio-nanocomposite coatings developed using arrowroot starch (AA), cellulose nanocrystals (CNC), carnauba wax nanoemulsion (CWN), and Cymbopogon martinii and Mentha spicata essential oils (CEO and MEO, respectively) on the physicochemical, microbiological, bioactive, antioxidant, and aromatic characteristics of strawberries cv. 'Oso Grande' in refrigerated storage for 12 days. The coatings improved the shelf life and stability of strawberries, minimizing their weight loss (2.6-3.9 %), as well as changes in color and texture (except for those coated with CEO), titratable acidity, pH, soluble solids, anthocyanins, phenolic compounds, ascorbic acid content, and antioxidant activity compared with uncoated control strawberries. The bio-nanocomposite coatings containing MEO and CEO also exhibited antimicrobial activity, reduced visible fungal deterioration (40-60 %), and reduced microbial load (3.59-4.03 log CFU g-1 for mesophilic aerobic bacteria and 4.45-5.22 log CFU g-1 for fungi and yeast) during storage. They also significantly reduced the severity of decay caused by inoculation with Botrytis cinerea or Rhizopus stolonifer. The coatings altered the volatile profile of the fruits during storage, decreasing aldehyde and alcohol concentrations and increasing ester concentrations. Thus, these bio-nanocomposite coatings, especially those containing MEO, can be used as antimicrobial coating materials to preserve the post-harvest quality of fresh strawberries.