Various potential sources of bioactive components exist in nature which are fairly underutilized due to the lack of a scientific approach that can be sustainable as well as practically feasible. The recovery of bioactive compounds is a big challenge and its use in food industry to develop functional foods is a promising area of research. Various techniques are available for the extraction of these bioactives but due to their thermolabile nature, there is demand for nonthermal or green technologies which can lower the cost of operation and decrease operational time and energy consumption as compared to conventional methods. Ultrasound-assisted extraction (UAE) is gaining popularity due to its relative advantages over solvent extraction. Thereafter, ultrasonication as an encapsulating tool helps in protecting the core components against adverse food environmental conditions during processing and storage. The review mainly aims to discuss ultrasound technology, its applications, the fundamental principles of ultrasonic-assisted extraction and encapsulation, the parameters affecting them, and applications of ultrasound-assisted extraction and encapsulation in food systems. Additionally, future research areas are highlighted with an emphasis on the energy sustainability of the whole process.

With the ever-increasing global population, it is impossible to meet the demand for animal protein by relying only on conventional methods due to the depleting natural resources. It is very challenging to ensure a sustainable supply of animal proteins from a single source or form and requires a holistic approach by using all suitable options. The present review critically reviewed various technological, sustainability, nutritional value, regulatory framework, food safety challenge, and prospect aspects of plant-based meat analogs, in vitro meat, edible insect, and single-cell proteins as suitable candidates for future food security and supply of animal protein in a sustainable way. For in vitro meat, the technological challenge in the supply of raw inputs, large-size bioreactors, and scale-up remains a major issue. Although having a lower environmental impact, the acceptance of edible insects to more comprehensive sections and associated food safety risks remains a major concern. There is a need for uniform and proper regulations of these alternatives/novel foods across the globe, covering various aspects throughout the food supply chain. Plant-based meat analogs, in vitro meat, insects, and single-cell proteins along with conventional meat can meet the demand for high-quality protein in the near future.

Treating livestock as senseless production machines has led to rampant depletion of natural resources, enhanced greenhouse gas emissions, gross animal welfare violations, and other ethical issues. It has essentially instigated constant scrutiny of conventional meat production by various experts and scientists. Sustainably in the meat sector is a big challenge which requires a multifaced and holistic approach. Novel tools like digitalization of the farming system and livestock market, precision livestock farming, application of remote sensing and artificial intelligence to manage production and environmental impact/GHG emission, can help in attaining sustainability in this sector. Further, improving nutrient use efficiency and recycling in feed and animal production through integration with agroecology and industrial ecology, improving individual animal and herd health by ensuring proper biosecurity measures and selective breeding, and welfare by mitigating animal stress during production are also key elements in achieving sustainability in meat production. In addition, sustainability bears a direct relationship with various social dimensions of meat production efficiency such as non-market attributes, balance between demand and consumption, market and policy failures. The present review critically examines the various aspects that significantly impact the efficiency and sustainability of meat production.

SUMMARY Palm kernel cake (PKC) is a by-product of oil extraction from palm fruits and has been included in poultry diets as an alternative to soybean meal and yellow corn. Due to its high content of fibre, coarse texture and gritty appearance, the use of PKC in poultry nutrition is limited. In order to increase the nutritive value of PKC, there is a tendency nowadays to create solid state fermentation (SSF) by using cellulolytic microbes. This paper reviews the impact of feeding fermented and non-fermented PKC on the performance of broiler chickens. Recent studies have reported that SSF by cellulolytic microorganisms improved the nutritive value of PKC. The nutrient digestibility has been increased significantly in PKC fermented using Paenibacillus polymyxya ATCC 842 or Weisella confusa SR-17b. The availability of valine, histidine, methionine and arginine was 70.42%, 71.50%, 71.92% and 81.15%, respectively, in PKC fermented using P. polymyxa ATCC 842. The digestibility of crude protein (CP) increased by 61.83% and 59.90% in PKC fermented using P. polymyxya ATCC 842 or W. confusa SR-17b, respectively. In addition, body weight gain (BWG) and feed conversion ratio (FCR) improved significantly in broilers fed 15% fermented PKC compared to those fed 15% non-fermented PKC (2000.43 g versus 1823.23 g and 1.75 versus 1.91, respectively). The intestinal Enterobacteriaceae decreased (4.03 CFU/g) and lactic acid bacteria increased (5.56 CFU/g) in birds fed 15% PKC fermented by P. polymyxa ATCC 842. Therefore, fermented PKC can be included in a broiler diet up to 15%, replacing part of soybean and yellow corn in the diet, leading to a decrease in the overall cost of poultry feeding.