We propose new burst assembly techniques that aim at reducing the average delay experienced by the packets during the burstification process in optical burst switched (OBS) networks, for a given average size of the bursts produced. These techniques use a linear prediction filter to estimate the number of packet arrivals at the ingress node in the following interval, and launch a new burst into the network when a certain criterion, which is different for each proposed scheme, is met. Reducing the packet burstification delay, for a given average burst size, is essential for real-time applications; correspondingly, increasing the average burst size for a given packet burstification delay is important for reducing the number of bursts injected into the network and the associated overhead imposed on the core nodes. We evaluate the performance of the proposed schemes and show that two of them outperform the previously proposed timer - based, length - based and average delay-based burst aggregation schemes in terms of the average packet burstification delay for a given average burst size.